HVAC System - Automatic: Diagnosis — Ford Taurus IV (1999-2004)

PRELIMINARY INSPECTION

Verify customer complaints by operating Electronic Automatic Temperature Control (EATC) system in all available modes. Carefully check the following for possible cause of problems and repair as necessary: damaged/misrouted vacuum hoses, system components, damaged A/C compressor drive belt, open fuses, damaged/misrouted wiring circuits, and damaged/disconnected connectors.
If symptom(s) remain after preliminary inspection, connect New Generation Star Tester (007-00500), or scan tool, to Data Link Connector (DLC). Perform DATA LINK DIAGNOSTIC TEST using scan tool.
If scan tool displays CKT 914 and CKT 915 = ALL MODULE NO RESP/NOT EQUIP, go to appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT. Test and repair these circuits before proceeding.
If any EATC system related Powertrain Control Module (PCM) Diagnostic Trouble Code (DTC) is retrieved, go to «PCM DIAGNOSTIC TROUBLE CODES»(ref-62841-S00257545482001011900000) table. If no DTCs exist, diagnose by symptom. See «SYMPTOM INDEX»(ref-62841-S20961049012001022100000) table under SYMPTOM TESTS.
If RCC module cannot be accessed by New Generation Star Tester (007-00500), go to «TEST A: NO COMMUNICATION WITH RCC MODULE»(ref-62841-S35973027642001011900000) under SYMPTOM TESTS. The RCC module self-diagnostic test will detect problems in system control functions. It will display hard DTCs and intermittent DTCs during system operation.
The RCC module self-diagnostic test will NOT detect concerns associated with data link (module communication) messages, an NGS tester will have to be used to retrieve these messages. See appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT.

DTC	Description	Perform Test
P1460	WOT A/C Primary Circuit Malfunction	(1)
P1464	A/C Demand Out Of Self-Test Range	(1)
P1469	Low A/C Cycling Period	(1)
P1474	Low Fan Control (LFC) Primary Circuit Failure	(2)
P1479	High Fan Control (HFC) Primary Circuit Failure	(2)
(1) See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. (2) See ELECTRIC COOLING FANS, EEC-V - ALL MODELS article.

(1)	See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

(2)	See ELECTRIC COOLING FANS, EEC-V - ALL MODELS article.

PCM DIAGNOSTIC TROUBLE CODES

SYMPTOM TESTS

Note. For tests not covered in this article, see MANUAL A/C-HEATER SYSTEMS - SABLE & TAURUS article.

Symptom	Perform Test
No Communication With RCC Module	A
EATC System Inoperative, Intermittent Or Improper Operation	B
Improper/Erratic Airflow From Outlets	C
Insufficient, Erratic Or No Heat	D
A/C Does Not Operate Or Does Not Operate Properly	E
A/C Is Always On	F
Blower Motor Does Not Operate	G
Blower Motor Operates Continuously In High Speed	H
Blower Motor Inoperative In Some Speeds	I
Temperature Set Point Does Not Repeat After Turning Ignition Off	J
Temperature Display Will Not Shift Between Fahrenheit & Celsius	K

SYMPTOM INDEX

TEST A: NO COMMUNICATION WITH RCC MODULE

Turn ignition off. Disconnect Remote Climate Control (RCC) 26-pin harness connector C228. Measure resistance between ground and RCC module harness connector C228 terminal No. 8 (Black/White wire). (Scheme 7) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Black/White wire between RCC and ground. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure voltage between ground and RCC module harness connector C228 terminal No. 11 (White/Red wire). If more than 10 volts exists, go to next step. If 10 volts or less exists, repair open in White/Red wire between RCC module and central junction box fuse No. 216. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Turn ignition on. Measure voltage between ground and RCC module harness connector C228 terminal No. 10 (Violet/Orange wire). If more than 10 volts exists, go to next step. If 10 volts or less exists, repair open in Violet/Orange wire between RCC module and central junction box fuse No. 228. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.

Scheme 7

Scheme 8

Scheme 8: TEST B: EATC SYSTEM INOPERATIVE, INTERMITTENT OR IMPROPER OPERATION

Perform Remote Climate Control (RCC) module self-test. See «ENTERING SELF-DIAGNOSTICS»(ref-62841-S19669312692001011900000) under SELF-DIAGNOSTICS. If any DTCs exist, see «EATC DIAGNOSTIC TROUBLE CODE INDEX»(ref-62841-S12702476792001011900000) table to continue diagnosis. If no DTCs exist, go to next step.
Exit RCC module self-test by pressing front defrost button. Turn radio on. Press and hold radio memory buttons No. 3 and 6 simultaneously until "SP" is displayed in radio display window of Integrated Control Panel (ICP). Press radio memory button No. 5. Note function symbols displayed in climate control display window of ICP. (Scheme 8) If display is correct, complete and not missing any elements, go to next step. If display is not correct, incomplete or missing elements, replace ICP. Recheck system operation.
Turn ignition on. Press blower speed manual override switch fully up and down. If blower motor speed and graphic display matches override switch commands, go to next step. If blower motor is inoperative, go to «TEST G: BLOWER MOTOR INOPERATIVE»(ref-62841-S31318582232001011900000). If blower motor operates only in high speed, go to «TEST H: BLOWER MOTOR OPERATES CONTINUOUSLY AT HIGH SPEED»(ref-62841-S34103985202001011900000). If blower motor operates in low speed only, go to «TEST I: BLOWER MOTOR INOPERATIVE IN SOME SPEEDS»(ref-62841-S27010444882001022300000).
Press F DEF (front defrost) manual override button. If outside air is discharged from windshield defrost vents and side window demisters, to next step. If outside air is not discharged from windshield defrost vents and side window demisters, go to «TEST C: IMPROPER/ERRATIC AIRFLOW FROM OUTLETS»(ref-62841-S07951906442001021400000).
Press FLOOR manual override button. If outside air discharges from floor duct, go to next step. If outside air does not discharge from floor duct, go to «TEST C: IMPROPER/ERRATIC AIRFLOW FROM OUTLETS»(ref-62841-S07951906442001021400000).
Press VENT manual override button. If outside air is discharged from instrument panel registers, go to next step. If outside air is not discharged from instrument panel registers, go to «TEST C: IMPROPER/ERRATIC AIRFLOW FROM OUTLETS»(ref-62841-S07951906442001021400000).
Ensure ambient temperature is over 41°F (5°C). Check for A/C compressor operation. If compressor clutch engages, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. If compressor clutch does not engage, go to next step.
Press MAX A/C manual override button. If recirculated air is discharged from instrument panel registers, go to next step. If recirculated air is not discharged from instrument panel registers, go to «TEST C: IMPROPER/ERRATIC AIRFLOW FROM OUTLETS»(ref-62841-S07951906442001021400000).
Check for A/C compressor operation in MAX A/C override position. If compressor clutch engages go to next step. If compressor clutch does not engage, go to «TEST E: A/C DOES NOT OPERATE OR DOES NOT OPERATE PROPERLY»(ref-62841-S10773942872001022300000).
Press AUTO button. If AUTO and selected temperature is displayed in climate control display window, go to next step. If AUTO and selected temperature is not displayed in climate control display window, replace ICP. Recheck system operation.
Press R DEF (rear defrost) manual override button. If indicator illuminates and rear widow defogs, system is operating properly at this time. If indicator does not illuminate and/or rear window does not defog, see appropriate REAR WINDOW DEFOGGERS article in ACCESSORIES & EQUIPMENT.

TEST C: IMPROPER/ERRATIC AIRFLOW FROM OUTLETS

Start engine and run at idle. Set blower motor switch to maximum. Press each manual override button. Check airflow at each setting. If airflow is only from defrost outlets in all positions, go to next step. If airflow is from other than defrost outlets, go to step 10 .
Turn ignition off. In engine compartment, check vacuum supply hose fittings at intake manifold and A/C vacuum check valve. If hose is disconnected or damaged at any of these points, repair or replace as needed. Recheck system operation. If hose connections are okay, go to next step.
Start engine and run at idle. Disconnect vacuum supply hose to vacuum reservoir from A/C vacuum check valve. Verify vacuum exists. Reconnect vacuum reservoir hose. Disconnect vacuum supply hose, from check valve, to control assembly source line. Verify vacuum exists. If vacuum exists at both check valve ports, go to next step. If vacuum does not exist at either or both ports, replace A/C vacuum check valve. Recheck system operation.
Turn ignition off. Disconnect A/C vacuum check valve connections. Connect vacuum pump, with a "T" fitting and two hoses attached to vacuum check valve ports (except port from intake manifold). Try to pull 15 in. Hg of vacuum. If vacuum leaks down more than 1 in. Hg of vacuum per minute, replace A/C vacuum check valve. Recheck system operation. If no vacuum loss occurs, go to next step.
Connect A/C vacuum check valve. Disconnect vacuum reservoir tank vacuum hose. With a vacuum pump, apply vacuum to reservoir supply hose and check for leaks. If vacuum leaks down more than 1 in. Hg of vacuum per minute, go to next step. If vacuum does not leak down more than 1 in. Hg of vacuum per minute, go to step 7 .
Disconnect vacuum hose at vacuum reservoir. Connect vacuum pump to vacuum reservoir. Apply vacuum to reservoir supply hose and check for leaks. If vacuum leaks down more than 1 in. Hg of vacuum per minute, replace vacuum reservoir. Recheck system operation. If vacuum does not leak down more than 1 in. Hg of vacuum per minute, repair or replace vacuum hose between A/C vacuum check valve and vacuum reservoir. Recheck system operation.
Disconnect plenum vacuum harness from Remote Climate Control (RCC) module. Plug Black supply line port in harness. Using vacuum pump, leak test Black vacuum line. If vacuum leaks down more than 1 in. Hg of vacuum per minute, repair or replace plenum vacuum harness. Recheck system operation. If vacuum does not leak down more than 1 in. Hg of vacuum per minute, go to next step.
Remove plug from Black supply hose port. Connect vacuum pump to Black supply hose at A/C check valve end and try to pull vacuum. If pump pulls full or partial vacuum, hose is plugged or restricted. If hose is plugged or restricted, replace blocked vacuum hose between intake manifold and A/C vacuum check valve. Recheck system operation. If hose is not plugged or restricted, go to next step.
Connect vacuum pump to supply port of RCC module and plug all other ports. Turn ignition on. Apply 15 in. Hg of vacuum at each manual override button. If vacuum leaks down more than 1 in. Hg of vacuum per minute, replace RCC module. Recheck system operation. If no leakage is indicated in vacuum harness, go to next step.
Repeat step 1 . If airflow is correct for each switch position, go to next step. If airflow is not correct, go to step 16 .
Set blower speed to maximum. If airflow goes to defrost outlets when accelerating, go to step 14 . If airflow does not go to defrost outlets, go to next step.
Turn ignition off. Determine if system functioned properly prior to this concern. If system did function properly, go to step 16 . If system did not function properly prior to current concern, go to next step.
Disconnect plenum vacuum harness from RCC module. Apply 15 in. Hg of vacuum to each line of plenum vacuum harness (except Black vacuum supply line). If vacuum leaks down more than 1 in. Hg of vacuum per minute, note vacuum line(s) that drop vacuum and go to next step. If vacuum does not drop more than 1 in. Hg of vacuum per minute, go to step 15 .
Check vacuum line connection to vacuum control motor of vacuum circuit that leaked down in step 13 . If vacuum hose is connected properly, go to next step. If vacuum hose is not connected properly, reconnect vacuum hose and recheck system operation.
Disconnect vacuum hose for vacuum motor corresponding to position where leak(s) were noted. Attach vacuum pump and apply vacuum. If vacuum control motor holds vacuum, replace jumper vacuum harness or plenum vacuum harness. If vacuum control motor leaks, replace motor and recheck system operation.
Check each vacuum hose to ensure it is not pinched or plugged. If any hose is pinched or plugged, repair or replace hose as necessary. Recheck system operation. If all hoses are not pinched or plugged, go to next step.
Disconnect each vacuum hose from each vacuum control motor. Apply vacuum to each port in plenum vacuum harness (except Black supply port). If vacuum pulls and holds, hose is plugged. If vacuum pump pulls a partial vacuum, hose is restricted. If any hose is plugged or restricted, repair or replace vacuum hose(s) as necessary. Recheck system operation. If hoses are not plugged or restricted, go to next step.
Compare vacuum hose color in each vacuum harness. See «VACUUM DIAGRAMS»(ref-62841-S11872536082001011900000) . If hose colors are correct, go to next step. If hose colors are incorrect, replace vacuum harness. Recheck system operation.
Check for proper installation and operation of vacuum control motor arms to air distribution doors. If vacuum control motors arms are connected and operate properly, check air distribution door for binding. Repair or replace air distribution door as necessary. If vacuum control motor arms are not connected properly or at all, reconnect arm as necessary and recheck system operation.

TEST D: INSUFFICIENT, ERRATIC OR NO HEAT

Check coolant level with engine cold and with engine hot. If coolant is at proper level, go to next step. If coolant is not at proper level, go to step 3 .
Start engine and run at normal operating temperature. Carefully feel heater core inlet hose at inlet connection. If hose is too hot to touch, go to step 4 . If hose is not hot, check and repair cooling system as needed.
Ensure coolant reservoir is filled to proper level. Pressure test cooling system and radiator cap. If cooling system holds pressure properly, go to next step. If cooling system does not hold pressure, repair cooling system as required.
With engine running at normal operating temperature, feel heater core outlet hose at outlet connection. If heater outlet hose is cool or cold, test heater core for plugged or restricted condition. If outlet hose is hot, go to «DTC B1249: BLEND DOOR FAILURE»(ref-62841-S09195065742001022100000) under SELF-DIAGNOSTICS.

TEST E: A/C DOES NOT OPERATE OR DOES NOT OPERATE PROPERLY

Note. Ensure ambient temperature is above 50°F (10°C).

Scheme 9

Scheme 9: TEST E: A/C DOES NOT OPERATE OR DOES NOT OPERATE PROPERLY

Scheme 10

Scheme 11

Turn ignition on. Turn function selector switch to OFF position. Connect scan tool following manufacturer's instructions. Perform PCM PID ACCS test. If PCM PID ACCS reads ON, perform PCM self-diagnostic test. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. If PCM PID ACCS does not read ON, go to next step.
Perform PCM PID WAC test. If PCM PID WAC reads ON, perform PCM self-diagnostic test. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. If PCM PID WAC does not read ON, go to next step. NOTE: If PID WAC is YES, it is the same fault as DTC P1460.
Run engine at idle. Set A/C-heater system to MAX A/C. Perform PCM PID ACCS test. If PID ACCS reads ON, go to next step. If PID ACCS does not read ON, go to step 5.
Start engine and run at idle. Set A/C-heater system to MAX A/C. Perform PCM PID WAC. If PID WAC reads ON, go to step 12. If PID WAC does not read ON, perform PCM self-diagnostic test. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
Turn ignition off. Disconnect pressure cut-off switch 4-pin harness connector C1062. Turn ignition on. Measure voltage between ground and pressure cut-off switch harness connector C1062 terminal No. 4 (Red/Yellow wire). (Scheme 9) If more than 10 volts exists, go to step 10. If 10 volts or less exists, go to next step.
Turn ignition off. Disconnect A/C cycling switch 4-pin harness connector C130. Turn ignition on. Measure voltage between ground and A/C cycling switch harness connector C130 terminal No. 1 (Violet wire). (Scheme 10) If more than 10 volts exists, go to next step. If 10 volts or less exists, go to step 8.
Turn ignition off. Connect a fused jumper between A/C cycling switch harness connector C130 terminals No. 1 (Violet wire) and No. 4 (Red/Yellow wire). Turn ignition on. Measure voltage between ground and pressure cut-off switch 4-pin harness connector C1062 terminal No. 4 (Red/Yellow wire). If more than 10 volts exists, go to step 9. If 10 volts or less exists, repair open in Red/Yellow wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Turn ignition off. Disconnect Remote Climate Control (RCC) module 26-pin harness connector C228. Measure resistance of Violet wire between RCC module harness connector C228 terminal No. 13 and A/C cycling switch harness connector C130 terminal No. 1. (Scheme 7)and (Scheme 10). If resistance is less than 5 ohms, replace RCC module. Recheck system operation. If resistance is 5 ohms or more, repair open or high resistance in Violet wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Turn ignition OFF. Connect manifold gauge set to service ports and observe pressure. If pressure is between 50 psi (3.5 kg/cm 2 ) and 250 psi (17.6 kg/cm 2 ), replace A/C cycling switch. Recheck system operation. If pressure is not between 50 psi (3.5 kg/cm 2 ) and 250 psi (17.6 kg/cm 2 ), check refrigerant system for leaks and service as needed. Recheck system operation.
Turn ignition off. Connect a fused jumper between pressure cut-off switch harness connector C1062 terminals No. 1 (Dark Green/White wire) and No. 4 (Red/Yellow wire). (Scheme 9) Turn ignition on. If compressor clutch engages, replace pressure cut-off switch. Recheck system operation. If compressor clutch does not engage, go to next step.
Turn ignition off. Remove fused jumper wire from pressure cut-off switch harness connector. Disconnect PCM 104-pin harness connector C175. Connect EEC-V 104-Pin Breakout Box (T94L-50-EEC-V) to PCM harness connector C175. DO NOT connect breakout box to PCM. Measure resistance between pressure cut-off switch C1062 terminal No. 1 (Dark Green/White wire) and breakout box pin No. 41. If resistance is less than 5 ohms, replace PCM. Recheck system operation. If resistance is 5 ohms or more, repair open or high resistance in Dark Green/White wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Turn ignition off. Disconnect A/C compressor clutch solenoid 2-pin harness connector C100. Turn ignition on. Measure voltage between A/C compressor clutch solenoid harness connector C100 Black/Yellow wire terminal. If more than 10 volts exists, go to next step. If 10 volts or less exists, go to step 14.
Turn ignition off. Measure resistance between ground and A/C clutch solenoid harness connector Black wire terminal. If resistance is less than 5 ohms, go to step 16. If resistance is 5 ohms or more, repair open or high resistance in Black wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Turn ignition off. Remove A/C clutch relay from battery junction box (located in front center of engine compartment). Measure resistance of Black/Yellow wire between A/C compressor clutch solenoid harness connector and A/C clutch relay socket terminal No. 5. (Scheme 11) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Black/Yellow wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Turn ignition on. Measure voltage between ground and A/C clutch relay socket terminal No. 3 (Pink/Light Blue wire). If more than 10 volts exists, go to step 17. If 10 volts or less exists, repair open in Pink/Light Blue wire between battery junction box fuse No. 122 and A/C clutch relay. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure A/C compressor clutch air gap at 3 equally spaced positions. If air gap is more than 0.033" (0.85 mm), adjust A/C compressor clutch air gap to 0.014-0.033" (0.35-0.85 mm). Recheck system operation. If air gap is not more than 0.033" (0.85 mm), replace A/C compressor clutch solenoid. Recheck system operation.
Turn ignition on. Measure resistance between ground and A/C clutch relay socket terminal No. 2 (Pink/Yellow wire). If resistance is less than 5 ohms, replace A/C clutch relay. If resistance is 5 ohms or more, go to next step.
Turn ignition off. Disconnect PCM 104-pin harness connector C175. Connect EEC-V 104-Pin Breakout Box (T94L-50-EEC-V) to PCM harness connector C175. DO NOT connect breakout box to PCM. Measure resistance between A/C clutch relay socket terminal No. 2 (Pink/Yellow wire) and breakout box pin No. 69. If resistance is less than 5 ohms, replace PCM. Recheck system operation. If resistance is 5 ohms or more, repair open or high resistance in Pink/Yellow wire between A/C clutch relay and PCM. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.

TEST F: A/C IS ALWAYS ON

Turn ignition on. Turn A/C-heater system OFF. Connect scan tool following manufacturer's instructions. Perform PCM PID WACF test. If PID WACF reads YES, repair short to ground in Pink/Yellow wire between PCM and A/C clutch relay. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation. If PID WACF does not read YES, go to next step.
Perform PCM PID ACCS test. If PCM PID ACCS reads ON, go to next step. If PCM PID ACCS does not read ON, go to step 7.
Turn ignition off. Disconnect A/C cycling switch 4-pin harness connector C130. Turn ignition on. Measure voltage between ground and A/C cycling switch harness connector C130 terminal No. 1 (Violet wire). (Scheme 10) If more than 10 volts exists, go to next step. If 10 volts or less exists, go to step 5.
Turn ignition off. Disconnect Remote Climate Control (RCC) module 26-pin harness connector C228. Turn ignition on. Measure voltage between ground and A/C cycling switch harness connector C1062 terminal No. 1 (Violet wire). If more than 10 volts exists, repair short to power in Violet wire between RCC and A/C cycling switch. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation. If 10 volts or less exists, replace RCC. Recheck system operation.
Turn ignition off. Disconnect pressure cut-off switch 4-pin harness connector C1062. Turn ignition on. Measure voltage between ground and pressure cut-off switch harness connector C1062 terminal No. 4 (Red/Yellow wire). If more than 10 volts exists, repair short to power in Red/Yellow wire between pressure cut-off switch and A/C cycling switch. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation. If 10 volts or less exists, go to next step.
Measure voltage between ground and pressure cut-off switch harness connector C1062 terminal No. 1 (Dark Green/White wire). (Scheme 9) If more than 10 volts exists, repair short to power in Dark Green/White wire between pressure cut-off switch and PCM. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation. If 10 volts or less exists, replace PCM. Recheck system operation.
Turn ignition off. Disconnect A/C clutch solenoid 2-pin harness connector C100. Turn ignition on. Measure voltage between ground and A/C cycling switch harness connector C100 Black/Yellow wire terminal. If more than 10 volts exists, go to next step. If 10 volts or less exists, go to step 9.
Turn ignition off. Remove A/C clutch relay from battery junction box (located in front center of engine compartment). Measure voltage between ground and A/C clutch solenoid harness connector C100 Black/Yellow wire terminal. If more than 10 volts exists, repair short to power in Black/Yellow wire between A/C clutch solenoid and A/C clutch relay. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation. If 10 volts or less exists, replace A/C clutch relay. Recheck system operation.
Measure A/C compressor clutch air gap at 3 equally spaced positions. If air gap is less than 0.014" (0.35 mm), adjust air gap to 0.014-0.033" (0.35-0.85 mm). Recheck system operation. If air gap is not less than 0.014" (0.35 mm), replace A/C compressor clutch solenoid. Recheck system operation.

Scheme 12

Scheme 12: TEST G: BLOWER MOTOR INOPERATIVE

Scheme 13

Turn ignition off. Disconnect blower motor speed control 5-pin harness connector C271a. Turn ignition on. Press AUTO manual override button on Integrated Control Panel (ICP). Measure voltage between ground and blower motor controller harness connector C271a terminal No. 1 (Pink/White wire). (Scheme 12) If more than 10 volts exists, go to step 13. If 10 volts or less exists, go to next step.
Turn ignition OFF. Remove blower motor relay from central junction box (located under left side of instrument panel). Measure voltage between ground and blower motor relay socket terminal No. 87. (Scheme 13) If more than 10 volts exists, go to step 7. If 10 volts or less exists, go to next step.
Remove and test central junction box fuse No. 208 (40-amp). If fuse No. 208 is open, go to next step. If fuse No. 208 is okay, repair open in White/Yellow wire between fuse No. 208 and battery junction box. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance between ground and blower motor relay socket terminal No. 30 (Pink/White wire). If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair open or high resistance in Pink/White wire between blower motor relay and blower motor speed controller.
Disconnect blower motor 2-pin harness connector C2006. Using Electrical Tester (010-00736), measure current draw between blower motor and a known-good battery. If current draw is 9.2 volts or less, go to next step. If current draw is more than 9.2 volts, replace blower motor. Recheck system operation.
Connect blower motor harness connector. Connect blower motor speed controller. Install central junction box fuse No. 208. Connect a 12-gauge (40-amp) jumper wire between blower motor relay socket terminals No. 30 and 87. If central junction box fuse No. 208 blows, replace blower motor speed controller. Recheck system operation. If fuse No. 208 does not blow, replace blower motor relay. Recheck system operation.
Turn ignition on. Measure voltage between ground and blower motor relay socket terminal No. 85. If more than 10 volts exists, go to next step. If 10 volts or less exists, go to step 11.
Turn ignition off. Disconnect Remote Climate Control (RCC) module 26-pin harness connector C228. Measure resistance of Yellow wire between RCC module harness connector C228 terminal No. 14 and blower motor relay socket terminal No. 86. (Scheme 7)and (Scheme 13). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Yellow wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance of Pink/White wire between blower motor speed controller harness connector C271a terminal No. 1 and blower motor relay socket terminal No. 30. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Pink/White wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Install blower motor relay. Turn ignition on. Connect a fused jumper wire between ground and RCC module harness connector C228 terminal No. 14 (Yellow wire). Measure voltage between ground and blower motor speed controller harness connector C271a terminal No. 1 (Pink/White wire). If more than 10 volts exists, replace RCC module. Recheck system operation. If 10 volts or less exists, replace blower motor relay. Recheck system operation.
Remove and test battery junction box fuse No. 228 (10-amp). If fuse No. 228 is blown, go to next step. If fuse No. 228 is not blown, repair open in Gray/Yellow wire between ignition switch and central junction box. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance between ground and blower motor relay socket terminal No. 85. If resistance is more than 10 k/ohms, replace blower motor relay. Recheck system operation. If resistance is 10 k/ohms or less, repair short to ground in Gray/Yellow wire between ignition switch and central junction box. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Turn ignition off. Disconnect blower motor speed controller 2-pin harness connector C271b. Turn ignition on. Connect a fused 12-gauge (40-amp) jumper wire between blower motor speed controller harness connector C271a terminal No. 1 (Pink/White wire) and blower motor speed controller harness connector C271b terminal No. 1 (Pink/White wire). Connect a second fused 12-gauge (40-amp) jumper wire between blower motor speed controller harness connector C271a terminal No. 2 (Black wire) and blower motor speed controller harness connector C271b terminal No. 2 (Black wire). If blower motor operates at high speed, go to step 17. If blower motor does not operate at high speed, go to next step.
Turn ignition off. Disconnect blower motor 2-pin harness connector C2006. Measure resistance of Pink/White wire between blower motor speed controller harness connector C271b terminal No. 2 and blower motor harness connector C2006 terminal No. 1. If resistance is less than 5 ohms, go to next step. If resistance in 5 ohms or more, repair open or high resistance in Pink/White wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance of Orange/Black wire between blower motor speed controller harness connector C271a terminal No. 2 and blower motor harness connector C2006 terminal No. 2. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Orange/Black wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance between ground and blower motor speed controller harness connector C271a terminal No. 2 (Black wire). If resistance is less than 5 ohms, replace blower motor. Recheck system operation. If resistance is 5 ohms or more, repair open or high resistance in Black wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Turn ignition off. Remove jumper wires. Connect blower motor speed controller. Turn ignition on. Press MAX A/C manual override button on ICP. Set blower speed to high. Using voltmeter connected to ground, backprobe blower motor speed controller harness connector C271a terminal No. 3 (Orange/Black wire). If about 5 volts exists, replace blower motor speed controller. Recheck system operation. If about 5 volts does not exist, go to next step.
Turn ignition off. Disconnect RCC module 26-pin harness connector C228. Measure resistance of Orange/Black wire between RCC module harness connector C228 terminal No. 24 and blower motor speed controller harness connector C271a terminal No. 3. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Orange/Black wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance between ground and blower motor speed controller harness connector C271a terminal No. 3 (Orange/Black wire). If resistance is more than 10 k/ohms, replace RCC module. Recheck system operation. If resistance is 10 k/ohms or less, repair short to ground in Orange/Black wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.

TEST H: BLOWER MOTOR OPERATES CONTINUOUSLY AT HIGH SPEED

Turn ignition on. Press MAX A/C manual override button on ICP. Set blower speed to low. If blower motor speed reduces, system is okay at this time. If blower motor speed does not reduce, go to next step.
Press OFF manual override button on ICP. Using voltmeter connected to ground, backprobe blower motor speed controller harness connector C271a terminal No. 3 (Orange/Black wire). (Scheme 12) If more than one volt exists, go to next step. If one volt or less exists, go to step 4.
Turn ignition off. Disconnect Remote Climate Control (RCC) module 26-pin harness connector C228. Turn ignition on. Using voltmeter connected to ground, backprobe blower motor speed controller harness connector C271a terminal No. 3 (Orange/Black wire). If any voltage exists, repair short to power in Orange/Black wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation. If no voltage exists, replace RCC module. Recheck system operation.
Turn ignition off. Disconnect Remote Climate Control (RCC) module 26-pin harness connector C228. Measure resistance of Orange/Black wire between blower motor speed controller harness connector C271a terminal No. 3 and RCC module harness connector C228 terminal No. 24. (Scheme 7)and (Scheme 12). If resistance is less than 5 ohms, replace blower motor speed controller. Recheck system operation. If resistance in 5 ohms or more, repair open or high resistance in Orange/Black wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.

TEST I: BLOWER MOTOR INOPERATIVE IN SOME SPEEDS

Turn ignition off. Turn ignition on. Press MAX A/C manual override button on ICP. Using a voltmeter connected to ground, backprobe blower motor speed controller harness connector C271a terminal No. 3 (Orange/Black wire). (Scheme 12) Slowly adjust blower motor speed from low to high speed while observing voltmeter. If voltage continuously increases from about 2 volts to 5 volts, go to next step. If voltage does not continuously increase from 2 volts to 5 volts, replace RCC module. Recheck system operation.
Turn ignition off. Disconnect blower motor 2-pin harness connector C2006. Turn ignition on. Measure voltage between blower motor harness connector terminals. Slowly adjust blower motor speed from low to high speed while observing voltmeter. If voltage continuously and smoothly increases from about 9 volts to 12 volts, system is operating normally at this time. If voltage does not continuously and smoothly increase from about 9 volts to 12 volts, replace blower motor speed controller. Recheck system operation.

TEST J: TEMPERATURE SET POINT DOES NOT REPEAT AFTER TURNING IGNITION OFF

Check central junction box fuse No. 216 (15-amp). If fuse No. 216 is okay, go to next step. If fuse 218 is blown, repair short to ground in Red/White or White/Red wire between fuse No. 216 and RCC module. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Disconnect RCC module 26-pin harness connector C288. Measure voltage between ground and RCC module harness connector C228 terminal No. 11 (Red/White wire). (Scheme 7) If more than 10 volts exists, replace RCC module. Recheck system operation. If 10 volts or less exists, repair open in Red/White or White/Red wire between fuse No. 216 and RCC module. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.

TEST K: TEMPERATURE DISPLAY WILL NOT SHIFT BETWEEN FAHRENHEIT & CELSIUS

Select MAX A/C, then F-DEF (front defrost) manual override buttons on Integrated Control Panel (ICP). Check air distribution and control panel display. If air is distributed to proper locations and display matches buttons pressed, replace Remote Climate Control (RCC) module. Recheck system operation. If air is not distributed to proper locations and/or displays do not match buttons pressed, replace ICP. Recheck system operation.

SELF-DIAGNOSTICS

The Remote Climate Control (RCC) module self-diagnostic test will detect problems in system control functions. It will display hard DTCs and intermittent DTCs during system operation.

The RCC module self-diagnostic test will not detect concerns associated with data link (module communication) messages, an NGS tester will have to be used to retrieve these messages. See appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT.

ENTERING SELF-DIAGNOSTICS

Ensure in-car temperature is 40-90°F (4-32°C) as false in-car temperature sensor DTCs will be displayed. Simultaneously depress OFF and FLOOR buttons, then press AUTO button within 2 seconds. The display will show a dashed line in center of Integrated Control Panel (ICP) display window for up to 30 seconds while self-test is running. Record all DTCs displayed.
If DTCs are displayed, perform test indicated. See «EATC DIAGNOSTIC TROUBLE CODE INDEX»(ref-62841-S12702476792001011900000) table. If no DTCs are displayed, diagnose by symptom. See «SYMPTOM INDEX»(ref-62841-S20961049012001022100000) table under SYMPTOM TESTS.
Self-diagnostics are complete when 888 is displayed in center of ICP display window. Self-diagnostics can be initiated at any time with the resulting DTCs being displayed. Normal system operation is stopped when system is in self-diagnostic mode.

NGS Tester (DTC) Code (1)	Self-Test & (Intermittent) Run Time Code (2)	Problem Description
B1249	024 (022)	Blend Door Failure
B1251	031 (33)	In-Car Temperature Sensor Open
B1253	030 (32)	In-Car Temperature Sensor Short
B1255	041 (043)	Ambient Air Temperature Sensor Open
B1257	040 (042)	Ambient Air Temperature Sensor Short
B1260	051 (053)	Sunload Temperature Sensor Open
B1261	050 (052)	Sunload Temperature Sensor Short
U2005	N/A (195)	Communications Error Between ICP & RCC
U1073 (3)	N/A	Engine Coolant Temperature Signal
U1341 (3)	N/A	Vehicle Speed Signal
(1) New Generation Star Tester (007-00500) Diagnostic Trouble Code (DTC). (2) N/A (not applicable) indicates that no self-test code (no intermittent/run time code) is displayed. (3) See appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT.

(1)	New Generation Star Tester (007-00500) Diagnostic Trouble Code (DTC).

(2)	N/A (not applicable) indicates that no self-test code (no intermittent/run time code) is displayed.

(3)	See appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT.

EATC DIAGNOSTIC TROUBLE CODE INDEX

EXITING SELF-DIAGNOSTICS

To exit self-diagnostics and retain all intermittent DTCs, press TEMP (cooler) button on integrated control panel. The RCC module will retain DTCs, the display will then go blank.
To exit self-diagnostics and clear all DTCs, press F-DEF button on integrated control panel. Display window will show 888 and all function symbols for one second. The display will then go blank.

Scheme 14

Scheme 14: DTC B1249: BLEND DOOR FAILURE

Turn ignition off. Disconnect Remote Climate Control (RCC) module 26-pin harness connector C228. Connect a fused jumper wire between RCC module harness connector C228 terminals No. 22 (Orange wire) and No. 11 (Red/White wire). Connect a second fused jumper between RCC module harness connector C228 terminals No. 21 (Dark Blue/Light Green wire) and No. 8 (Black/White wire). (Scheme 7) If temperature blend door actuator drives clockwise, go to next step. If temperature blend door actuator does not drive clockwise, go to step 3.
Remove jumper wires. Connect fused jumper wire between RCC module harness connector C228 terminals No. 21 (Dark Blue/Light Green wire) and No. 11 (Red/White wire). Connect a second jumper wire between RCC module harness connector C228 terminals No. 22 (Orange wire) and No. 8 (Black/White wire). If temperature blend door actuator drives counterclockwise, go to step 8. If temperature blend door actuator does not drive counterclockwise, go to next step 9.
Disconnect blend door actuator 8-pin harness connector C289. Measure resistance between ground and RCC harness connector C228 terminal No. 21 (Dark Blue/Light Green wire). If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in Dark Blue/Light Green wire between RCC module and temperature blend door actuator. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance between ground and RCC harness connector C228 terminal No. 22 (Orange wire). If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in Orange wire between RCC module and temperature blend door actuator. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance of Dark Blue/Light Green wire between RCC module harness connector C228 terminal No. 21 and temperature blend door actuator harness connector C289 terminal No. 7. (Scheme 7)and (Scheme 14). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Dark Blue/Light Green wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance of Orange wire between RCC module harness connector C228 terminal No. 22 and temperature blend door actuator harness connector C289 terminal No. 8. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Orange wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Remove temperature blend door actuator. Reconnect temperature blend door actuator connector. With temperature blend door actuator driveshaft disengaged from temperature blend door. Connect a fused jumper wire between RCC module harness connector C228 terminals No. 22 (Orange wire) and No. 11 (Red/White wire). (Scheme 7) Connect a second fused jumper between RCC module harness connector C228 terminals No. 21 (Dark Blue/Light Green wire) and No. 8 (Black/White wire). Note actuator movement. Connect a fused jumper wire between RCC module harness connector C228 terminals No. 21 (Dark Blue/Light Green wire) and No. 11 (Red/White wire). Connect a second jumper wire between RCC module harness connector C228 terminals No. 22 (Orange wire) and No. 8 (Black/White wire). If temperature blend door actuator drives both clockwise and counterclockwise, repair blocked or binding temperature blend door as necessary. If temperature blend door actuator does not drive both clockwise and counterclockwise, replace temperature blend door actuator. Recheck system operation.
Drive temperature blend door actuator to full cool position (clockwise) by connecting jumper wires as in step 1. Measure resistance between RCC module harness connector C228 terminals No. 5 (Red/Light Green wire) and No. 20 (Red/White wire). If resistance is 5000-7000 ohms, go to step 13. If resistance is not 5000-7000 ohms, go to next step.
Disconnect temperature blend door actuator 8-pin harness connector C289. Measure resistance of Red/Light Green wire between RCC module harness connector C228 terminal No. 5 and temperature blend door actuator harness connector C289 terminal No. 6. (Scheme 7)and (Scheme 14). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Red/Light Green wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance of Red/White wire between RCC module harness connector C228 terminal No. 20 and temperature blend door actuator harness connector C289 terminal No. 5. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Red/White wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance between ground and RCC module harness connector C228 terminal No. 5 (Red/Light Green wire). If resistance is more than 10 k/ohms go to next step. If resistance is 10 k/ohms or less, repair short to ground in Red/Light Green wire between RCC module and temperature blend door actuator. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance between ground and RCC module harness connector C228 terminal No. 20 (Red/White wire). If resistance is more than 10 k/ohms, replace temperature blend door actuator. If resistance is 10 k/ohms or less, repair short to ground in Red/White wire between RCC module and temperature blend door actuator. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Drive temperature blend door actuator to full cool position (clockwise) by connecting jumper wires as in step 1. Measure resistance between RCC module harness connector C228 terminals No. 5 (Red/Light Green wire) and No. 9 (Yellow/Light Green wire). If resistance is 5-7 k/ohms, go to step 16. If resistance is not 5-7 k/ohms, go to next step.
Measure resistance of Yellow/Green wire between RCC module harness connector C228 terminal No. 9 and temperature blend door actuator harness connector C289 terminal No. 1. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Yellow/Green wire.
Measure resistance between ground and RCC module harness connector C228 terminal No. 9 (Yellow/Light Green wire). If resistance is more than 10 k/ohms, replace temperature blend door actuator. If resistance is 10 k/ohms or less, repair short to ground in Yellow/Light Green wire between RCC module and temperature blend door actuator. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Operate temperature blend door actuator to full cool (clockwise) by connecting jumper wires as in step 1. Measure resistance between RCC module harness connector C228 terminals No. 5 (Red/Light Green wire) and No. 9 (Yellow/Light Green wire). If resistance is 3.5-6 k/ohms, go to next step. If resistance is not 3.5-6 k/ohms, replace temperature blend door actuator. Recheck system operation.
Measure resistance between ground and RCC module harness connector C228 terminal No. 5 (Red/Light Green wire). If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in Red/Light Green wire between RCC module and temperature blend door actuator. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance between ground and RCC module harness connector C228 terminal No. 20 (Red/White wire). If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in Red/White wire between RCC module and temperature blend door actuator. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance between ground and RCC module harness connector C228 terminal No. 9 (Yellow/Light Green wire). If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in Yellow/Light Green wire between RCC module and temperature blend door actuator. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.

DTC 1251: IN-CAR TEMPERATURE SENSOR OPEN

Turn ignition off. Disconnect in-car temperature sensor 3-pin harness connector C233. Measure resistance between in-car temperature sensor terminals. See «IN-CAR TEMPERATURE SENSOR RESISTANCE TEST»(ref-62841-S32699557732001011900000) table. If resistance is within specifications, go to next step. If resistance is not within specifications, replace in-car temperature sensor and recheck system operation.
Turn ignition on. Press AUTO button on EATC panel. Measure voltage between in-car temperature sensor harness connector C233 terminals No. 1 (Pink/Black wire) and No. 3 (White/Orange wire). (Scheme 15) If 4.7-5.1 volts exists, replace RCC. Recheck system operation. If 4.7-5.1 volts does not exist, go to next step.
Turn ignition OFF. Disconnect RCC module 26-pin harness connector C228. Measure resistance of White/Orange wire between RCC module harness connector C228 terminal No. 23 and in-car temperature sensor harness connector C233 terminal No. 3. (Scheme 7)and (Scheme 15). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in White/Orange wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.
Measure resistance of Pink/Black wire between RCC module harness connector C228 terminal No. 15 and in-car temperature sensor harness connector C233 terminal No. 1. If resistance is less than 5 ohms, replace RCC module. Recheck system operation. If resistance is 5 ohms or more, repair open or high resistance in Pink/Black wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.

Temperature °F (°C)	Ohms
50-68 (10-20)	37,000-58,000
68-86 (20-30)	24,000-37,000
86-104 (30-40)	16,000-24,000

IN-CAR TEMPERATURE SENSOR RESISTANCE TEST

Scheme 15

DTC 1253: IN-CAR TEMPERATURE SENSOR SHORT

Turn ignition off. Disconnect in-car temperature sensor 3-pin harness connector C233. Measure resistance between in-car temperature sensor terminals. See «IN-CAR TEMPERATURE SENSOR RESISTANCE TEST»(ref-62841-S05163755682001022200000) table. If resistance is within specifications, go to next step. If resistance is not within specifications, replace in-car temperature sensor and recheck system operation.
Turn ignition on. Press AUTO button on EATC panel. Measure voltage between in-car temperature sensor harness connector C233 terminals No. 1 (Pink/Black wire) and No. 3 (White/Orange wire). (Scheme 15) If 4.7-5.1 volts exists, replace RCC. Recheck system operation. If 4.7-5.1 volts does not exist, go to next step.
Turn ignition OFF. Disconnect RCC module 26-pin harness connector C228. Measure resistance between ground and in-car temperature sensor harness connector C233 terminal No. 3 (White/Orange wire). If resistance is less than 5 ohms, replace RCC module. Recheck system operation. If resistance is 5 ohms or more, repair open or high resistance in White/Orange wire. See «WIRING DIAGRAMS»(ref-62841-S07047853232001011900000). Recheck system operation.

Temperature °F (°C)	Ohms
50-68 (10-20)	37,000-58,000
68-86 (20-30)	24,000-37,000
86-104 (30-40)	16,000-24,000