A/c-Heater System - Automatic: Other Nissan Maxima A32

A/C-HEATER CONTROL PANEL

Operating mode, set temperature, discharge air outlet selection and fan speed are shown on display screen. (Scheme 4) Push button functions include

Auto Switch

A/C compressor, blower speed, air intake, air mix and mode doors are automatically controlled to reach and maintain set temperature.

Econ Switch

Full automatic control with A/C compressor off; system will not cool or dehumidify. System will maintain in-vehicle temperature if set temperature is above ambient temperature.

Temperature Switch

UP/DOWN push buttons increase or decrease set temperature.

Off Switch

A/C compressor and blower are off, intake doors are set to outside air position. Mode doors are set to foot (78%) and defrost (22%) position. System tries to maintain last set temperature using flow-through ventilation.

Fan Switch

UP/DOWN push buttons allow manual blower control. Speed selection (low, medium low, medium high, high) is shown on display screen.

Mode Switch

Push button allows manual control of air discharge outlets. Mode selection (face, bi-level, foot, defrost/foot) is shown on display screen.

Rec Switch

When rec button is on, inside air is recirculated. When rec button is off, automatic control resumes. When auto, defrost, or econ is selected, recirculation is canceled. Recirculation resumes when any other mode is selected.

Def Switch

Positions mode doors to defrost and air intake doors to outside (fresh) air. A/C compressor operates if ambient temperature is above 35°F (2°C).

Scheme 4

AIR MIX DOOR MOTOR

The air mix door motor is attached to the heater unit. The auto amplifier controls the air mix door motor, which moves the air mix door to a set position. Air mix door position is monitored by a Potentiometer Balance Resistor (PBR), which is part of the air mix door motor. Door position is fed back to the auto amplifier by the PBR.

AMBIENT TEMPERATURE SENSOR

An ambient temperature sensor, located below the hood latch, senses ambient temperature. The auto amplifier uses the signal from this sensor for controlling in-vehicle temperature.

ASPIRATOR

The aspirator, located at lower front of heater unit, produces a suction from outlet air discharged from heater unit. This suction draws air over the in-vehicle temperature sensor.

AUTO AMPLIFIER (BODY CONTROL MODULE)

The auto amplifier, built into Body Control Module (BCM), processes information from A/C-heater control panel and various sensors. The auto amplifier controls air mix door motor, mode door motor, intake door motor, fan motor and compressor operation. Self-diagnostic functions are built into the auto amplifier to check malfunctions in A/C-heater system. (Scheme 5)

FAN CONTROL AMPLIFIER

A fan control amplifier, located on the evaporator housing, controls blower motor speed. Operating voltage range is 4-12 volts. (Scheme 5)

INTAKE DOOR MOTOR

The intake door motor, mounted on the blower motor unit, is controlled by auto amplifier. (Scheme 5) This motor selects either fresh or recirculated air.

IN-VEHICLE TEMPERATURE SENSOR

In-vehicle temperature sensor is located in A/C-heater control panel, to right of display screen. (Scheme 5) Passenger compartment air is drawn through sensor by an aspirator. The auto amplifier uses a signal from this sensor for controlling in-vehicle temperature.

MODE DOOR MOTOR

The mode door motor, attached to the heater unit, directs discharge air to various outlets. It is controlled by the auto amplifier.

POTENTIOMETER BALANCE RESISTOR (PBR)

This variable resistor is built into the air mix door motor. It provides air mix door position to the auto amplifier.

Scheme 5

Scheme 6

POTENTIOMETER TEMPERATURE CONTROL

Note. Potentiometer temperature control may be referred to as a "potentio" temperature control in diagnostic charts.

Potentiometer Temperature Control (PTC) is built into A/C-heater control panel. Temperature can be set in 2°F increments. Temperature is digitally displayed.

SUNLOAD SENSOR

The sunload sensor is a photo-diode located on the right defroster grille. Sunlight is converted into a signal which is processed by the auto amplifier.

THERMAL TRANSMITTER

Thermal transmitter is mounted on left rear of engine. Sensor converts coolant temperature into a resistance value, which is sent to auto amplifier.

INTAKE DOOR

1. Install intake door motor onto intake unit. Connect wiring harness. (Scheme 5) Enter self-diagnosis step 4. Command Code 41. See «SELF-DIAGNOSIS STEP 4»(ref-35561-S29085143742001010900000) under SELF-DIAGNOSTICS.
2. Move intake door link by hand while holding intake door in recirculated air position. (Scheme 7) Connect intake door motor rod to intake door link rod holder. Verify intake door moves to correct positions when commanding Codes 41-46.

Scheme 7

MODE DOOR

1. Install mode door motor onto heater unit. Connect wiring harness. (Scheme 5) Enter self-diagnosis step 4. Command Code 46. See «SELF-DIAGNOSIS STEP 4»(ref-35561-S29085143742001010900000) under SELF-DIAGNOSTICS.
2. Move side link by hand while holding mode door in defrost position. Connect mode door motor rod to side link rod holder. (Scheme 8)
3. Verify mode door moves to the correct positions while the commanding Codes 41-46. See «SELF-DIAGNOSIS STEP 4»(ref-35561-S29085143742001010900000) under SELF-DIAGNOSTICS.

Scheme 8

Preliminary Information

The Engine Control Module (ECM) may be referred to as the Engine Concentrated Control System (ECCS) control unit. The A/C-heater control panel may also be called the push control unit in the trouble shooting charts. Perform PRELIMINARY CHECKS prior to using the DIAGNOSTIC PROCEDURE charts.

Air Outlet Does Not Change

1. Perform «SELF-DIAGNOSIS STEP 1»(ref-35561-S28187521602001010900000) and SELF-DIAGNOSIS STEP 2 under SELF-DIAGNOSTICS. If Code 20 appears after about 3 seconds, go to next step. If Code 20 does not appear, go to appropriate DIAGNOSTIC PROCEDURE. See «IDENTIFYING TROUBLE CODES»(ref-35561-S03212636752001010900000) table. IDENTIFYING TROUBLE CODES Code Number Diagnostic Procedure 21 Or -21 «1»(ref-35561-S12213081032001010900000) 22 Or -22 «2»(ref-35561-S33012184032001010900000) 23 Or -23 «3»(ref-35561-S17376293862001010900000) 25 Or -25 «4»(ref-35561-S29601706422001010900000) 26 Or -26 «5»(ref-35561-S41994214012001010900000)
2. Perform «SELF-DIAGNOSIS STEP 3»(ref-35561-S23987535762001010900000) under SELF-DIAGNOSTICS. If Code 30 appears after about 3 seconds, go to next step. If Code 30 does not appear after about 3 seconds, go to «DIAGNOSTIC PROCEDURE 6»(ref-35561-S14947828322001010900000) .
3. Perform «SELF-DIAGNOSIS STEP 4»(ref-35561-S29085143742001010900000) under SELF-DIAGNOSTICS. If air outlet changes according to each code, air outlet control system is normal. See «MODE DOOR CODES»(ref-35561-S34459826942001010900000) table. If air outlet does not change properly, check side link mechanism adjustment. If side link mechanism is okay, go to «DIAGNOSTIC PROCEDURE 6»(ref-35561-S14947828322001010900000) .

MODE DOOR CODES

Intake Door Does Not Move

1. Perform «SELF-DIAGNOSIS STEP 1»(ref-35561-S28187521602001010900000) and SELF-DIAGNOSIS STEP 2 under SELF-DIAGNOSTICS. If Code 20 appears after about 3 seconds, go to next step. If Code 20 does not appear, go to appropriate DIAGNOSTIC PROCEDURE. See «IDENTIFYING TROUBLE CODES»(ref-35561-S03212636752001010900000) table under PRELIMINARY CHECK 1.
2. Check intake temp sensor circuit. See «DIAGNOSTIC PROCEDURE»(ref-35561-S29601706422001010900000) 4. Perform «SELF-DIAGNOSIS STEP 4»(ref-35561-S29085143742001010900000) under SELF-DIAGNOSTICS. If air intake changes according to each code, air intake control system is normal. See INTAKE DOOR MOTOR CODES table. If air intake does not change properly, check linkage adjustment. If linkage is okay, go to «DIAGNOSTIC PROCEDURE 7»(ref-35561-S04536860902001010900000) .

INTAKE DOOR MOTOR CODES

Insufficient Cooling

1. Check mode door, intake door, blower, and compressor clutch for proper operation. If all are okay, go to next step. If any of these components does not operate properly, perform PRELIMINARY CHECK 1, 2, 5, or 6 as appropriate. Check compressor drive belt tension, and adjust as necessary. See «A/C SYSTEM SPECIFICATIONS»(ref-35561-S22848460072001010900000) table.
2. Check air mix door operation. If air mix door operates properly, go to next step. If air mix door does not operate properly, go to «PRELIMINARY CHECK 7»(ref-35561-S25337215822001010900000) .
3. Check radiator fans for proper operation. If okay, go to next step. If not okay, go to «RADIATOR FAN CIRCUITS»(ref-35561-S38200614712001010900000) under TESTING.
4. Connect A/C manifold gauge set. Test A/C system performance. See «A/C SYSTEM PERFORMANCE»(ref-35561-S21211074682001010900000) under TESTING. If A/C system performance is okay, go to next step. If A/C system performance is not okay, repair or recharge A/C system as necessary.
5. Check for evaporator coil freeze-up. Ensure center vent air is discharged sufficiently. If evaporator freeze-up does not occur, go to next step. If evaporator freeze-up occurs, go to «PRELIMINARY CHECK 6»(ref-35561-S01820300772001010900000) .
6. Inspect ducts for leaks, repair leaks as necessary. If no leaks exist, go to «AUXILIARY MECHANISM SETTING»(ref-35561-S26615870512001010900000) under SELF-DIAGNOSTICS.

PRELIMINARY CHECK 4

Note. To prevent unnecessary service of heating system, perform AUXILIARY MECHANISM SETTING under SELF-DIAGNOSTICS before proceeding with PRELIMINARY CHECK 4.

Insufficient Heating

1. Check mode door and blower for proper operation. If mode door and blower are okay, go to next step. If mode door or blower does not operate properly, perform «PRELIMINARY CHECK 1»(ref-35561-S39529452622001010900000) or 5 as appropriate.
2. Check for proper coolant level, kinked or leaking hoses, faulty radiator cap or air in cooling system. Repair or replace as necessary. Check air mix door operation. If air mix door operates properly, go to next step. If air mix door does not operate properly, go to «PRELIMINARY CHECK 7»(ref-35561-S25337215822001010900000) .
3. Inspect ducts for leaks, and repair as necessary. If no leaks exist, check by feel inlet and outlet heater hoses. If both heater hoses are warm, go to next step. If both hoses are cold, check thermostat installation and operation. Replace if necessary.
4. Ensure heater hoses are properly installed. Back-flush heater core and refill system with coolant. Recheck heater hoses by feel. If both hoses are warm, replace heater core. If inlet hose is hot and outlet hose is warm, heating system is okay.

Blower Motor Malfunctions

1. Perform «SELF-DIAGNOSIS STEP 1»(ref-35561-S28187521602001010900000) and SELF-DIAGNOSIS STEP 2 under SELF-DIAGNOSTICS. If Code 20 appears after about 3 seconds, go to next step. If Code 20 does not appear, go to appropriate DIAGNOSTIC PROCEDURE. See «IDENTIFYING TROUBLE CODES»(ref-35561-S03212636752001010900000) table under PRELIMINARY CHECK 1.
2. Check intake temp sensor circuit. See «DIAGNOSTIC PROCEDURE»(ref-35561-S29601706422001010900000) 4. Perform «SELF-DIAGNOSIS STEP 4»(ref-35561-S29085143742001010900000) under SELF-DIAGNOSTICS. If blower motor speed changes according to each code, go to next step. See «BLOWER MOTOR CODES»(ref-35561-S38744447932001010900000) table. If blower does not operate properly, go to «DIAGNOSTIC PROCEDURE 9»(ref-35561-S15736472022001010900000) .
3. Determine ambient and engine coolant temperatures. If coolant temperature is below 122°F (50°C) and ambient temperature is below 59°F (15°C), go to next step. If temperatures are not as specified, blower operation is normal.
4. If ambient and engine coolant temperatures are very cold, it is normal for the blower to delay operation for up to 3 minutes. After initial delay, blower will operate at low speed until coolant temperature is above 122°F (50°C). If temperatures are not cold, test thermal transmitter circuit.

BLOWER MOTOR CODES

Compressor Clutch Does Not Engage

1. Perform «SELF-DIAGNOSIS STEP 1»(ref-35561-S28187521602001010900000) and SELF-DIAGNOSIS STEP 2 under SELF-DIAGNOSTICS. If Code 20 appears after about 3 seconds, go to next step. If Code 20 does not appear, go to appropriate DIAGNOSTIC PROCEDURE. See «IDENTIFYING TROUBLE CODES»(ref-35561-S03212636752001010900000) table under PRELIMINARY CHECK 1.
2. Check compressor clutch operation. Perform «SELF-DIAGNOSIS»(ref-35561-S29085143742001010900000) STEP 4 under SELF-DIAGNOSTICS. If A/C compressor (magnetic) clutch engages and disengages according to each code, clutch operation is okay. See A/C COMPRESSOR CLUTCH CODES table.
3. If clutch does not operate normally, connect manifold gauge set. Test A/C system performance. See «A/C SYSTEM PERFORMANCE»(ref-35561-S21211074682001010900000) under TESTING. If A/C system performance is okay, go to «DIAGNOSTIC»(ref-35561-S04019630492001010900000) PROCEDURE 10. If A/C system performance is not okay, repair as necessary.

A/C COMPRESSOR CLUTCH CODES

Discharge Air Temperature Does Not Change

1. Perform «SELF-DIAGNOSIS STEP 1»(ref-35561-S28187521602001010900000) and SELF-DIAGNOSIS STEP 2 under SELF-DIAGNOSTICS. If Code 20 appears after about 3 seconds, go to next step. If Code 20 does not appear, go to appropriate DIAGNOSTIC PROCEDURE. See «IDENTIFYING TROUBLE CODES»(ref-35561-S03212636752001010900000) table under PRELIMINARY CHECK 1.
2. Check air mix door operation. Perform «SELF-DIAGNOSIS STEP 4»(ref-35561-S29085143742001010900000) under SELF-DIAGNOSTICS. If discharge air temperature does not change as specified, go to next step. If discharge air temperature changes according to each code, air mix door operation is okay. See AIR MIX DOOR CODES table.
3. Check air mix door mechanism. See «AIR MIX DOOR ADJUSTMENT»(ref-35561-S30397093002001010900000) under ADJUSTMENTS. If air mix door mechanism is okay, go to «DIAGNOSTIC»(ref-35561-S21811706662001010900000) PROCEDURE 8.

AIR MIX DOOR CODES

MAIN POWER SUPPLY & GROUND CIRCUIT CHECK

Note. Auto amplifier (BCM) ground circuit check applies to Canadian built vehicles only.

1. Disconnect A/C-heater control panel (push control unit) wiring harness connector. Turn ignition on. Check voltage between a known good ground and terminal No. 3 (Pink wire) of wiring harness connector. If battery voltage is not present, repair wiring harness.
2. If battery voltage is present, turn ignition off. Check continuity between ground and terminal No. 7 (Black wire). If continuity is not present, repair ground circuit. If continuity is present, power supply and ground circuit are okay.

Auto Amplifier (BCM)

1. Turn ignition is off. Unplug auto amplifier connector. Turn ignition on. Measure voltage between ground and auto amplifier harness connector terminal No. 1 (Pink wire). If battery voltage does not exist, repair wiring as necessary.
2. If battery voltage is present, turn ignition off. Check continuity between ground and terminal No. 24 (Black wire). If continuity is not present, repair ground circuit. If continuity is present, power supply and ground circuit are okay.

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

Scheme 20

Scheme 21

Scheme 22

Scheme 23

Scheme 24

To properly diagnose this system, self-diagnostics should be performed in the following order

1. Read ENTERING/EXITING SELF-DIAGNOSTICS.
2. Perform «SELF-DIAGNOSIS STEPS 1»(ref-35561-S28187521602001010900000) -5.
3. Perform appropriate «PRELIMINARY CHECK»(ref-35561-S01031714862001010900000) for symptom diagnosis. PRELIMINARY CHECK charts refer technician to appropriate DIAGNOSTIC PROCEDURE charts. See «DIAGNOSTIC PROCEDURE»(ref-35561-S12213081032001010900000) charts.

Light Emitting Diodes (LEDs) & Segments

Step 1 starts automatically when self-diagnostics are entered. All LEDs and fluorescent display tubes should light. (Scheme 4) If any LED or segment does not light, replace A/C-heater control panel.

Open/Short Circuit In Sensor Circuits

1. Warm engine to normal operating temperature. Position vehicle to enable sunlight to shine on sunload sensor. Enter Self-Diagnosis Step 2 by pressing temperature switch up arrow on A/C-heater control panel. Display will light a 2. If all sensor circuits are okay and no trouble codes exist, display will change to Code 20 after about 4 seconds.
2. If a sensor circuit is faulty, circuit code number will flash on display. A shorted circuit will have a flashing "-" in front of the number 2. An open circuit will not display a flashing "-". If two sensor circuits are faulty, each circuit code number will blink twice. See SELF-DIAGNOSIS STEP 2 CODE EXPLANATIONS table to interpret each code.

SELF-DIAGNOSIS STEP 2 CODE EXPLANATIONS

Mode & Intake Door Position

1. To enter self-diagnosis step 3, press temperature switch up arrow. (Scheme 4) Display will light a 3. If all doors are operational, display will change to 30 after about 20 seconds.
2. If a door is faulty, appropriate code will flash. If 2 doors are faulty, each code number will blink twice. To interpret codes, see SELF-DIAGNOSIS STEP 3 CODE EXPLANATIONS table.

Note. If any mode or intake door motor position switch malfunctions, mode or intake door motor will also malfunction.

SELF-DIAGNOSIS STEP 3 CODE EXPLANATIONS

Temperature Detected By Sensors

1. To enter self-diagnosis step 5, press temperature switch up arrow. (Scheme 4) Display will light a 51. When defrost switch is pressed once, display will show temperature sensed by ambient temperature sensor.
2. Press defrost switch again; display will show temperature sensed by in-vehicle sensor. Press defrost switch again; display will return to 51. If temperature shown on display is greatly different from actual temperature, inspect sensor circuit. If sensor circuit is okay, test sensor. See appropriate sensor under «TESTING»(ref-35561-S14545119702001010900000).
3. Press REC switch. If multiplex communications are functioning properly, fluorescent display will illuminate 52. If fan symbol illuminates to right of 52, a past or current multiplex communication error between A/C-heater control panel and auto amplifier exists.
4. Disconnect negative battery cable for at least one minute to clear communication memory. Reconnect battery cable. Perform «SELF-DIAGNOSIS STEP 5»(ref-35561-S32187418882001010900000). If multiplex communication error still exists, go to «DIAGNOSTIC PROCEDURE 11»(ref-35561-S12213081032001010900000).

Temperature Setting Trimmer

1. Temperature setting trimmer compensates for small differences between temperature setting on display and actual temperature within a range of plus or minus 6°F (3°C).
2. With system in «SELF-DIAGNOSIS STEP 5»(ref-35561-S32187418882001010900000) , press fan switch. System is now in auxiliary mode to set trimmer. Each time temperature switch up or down arrow is pressed, temperature display changes in one-degree Fahrenheit increments.

Note. If battery is disconnected, temperature trimmer setting goes to 0° and will have to be reset.

A/C SYSTEM PERFORMANCE

1. Park vehicle out of direct sunlight. Close all doors. Open engine hood and driver-side window. Connect A/C manifold gauge set. Unplug ambient temperature sensor connector. Ambient temperature sensor is located near hood latch. Connect jumper wire between harness connector terminals. Determine relative humidity and ambient air temperature.
2. Set temperature control to maximum cold, mode control to face vent, and recirculation switch to recirculated air position. Set blower fan switch to highest position. Start and run engine at 1500 RPM.
3. After running A/C for 10 minutes, check high and low-side system pressures and outlet air temperature at center instrument panel vent. Refer to A/C SYSTEM PRESSURE TEST and «RECIRC-TO-DISCHARGE AIR TEMP»(ref-35561-S16119361692001010900000) tables to determine if system is operating within range.

A/C SYSTEM PRESSURE TEST (1)

RECIRC-TO-DISCHARGE AIR TEMP

A/C RELAY & RADIATOR FAN RELAY NO. 1

Remove suspected relay from vehicle. (Scheme 6) Continuity should not exist between relay terminals No. 3 and 5. (Scheme 25) Apply 12 volts to terminals No. 1 and 2. Continuity should exist between terminals No. 3 and 5. Replace relay if continuity is not as specified.

Scheme 25

RADIATOR FAN RELAYS NO. 2 & 3

Remove suspected relay from vehicle. (Scheme 6) Continuity should not exist between relay terminals No. 3 and 5, or between terminals No. 6 and 7. (Scheme 26) Apply 12 volts to terminals No. 1 and 2. Continuity should exist between terminals No. 3 and 5, and between terminals No. 6 and 7. Replace relay if continuity is not as specified.

Scheme 26

Turn ignition off. Unplug underhood ambient temperature sensor connector, located near hood latch. (Scheme 6) Measure resistance between sensor terminals at specified temperatures. See AMBIENT & IN-VEHICLE TEMPERATURE SENSOR SPECIFICATIONS table. Replace sensor if resistance is not as specified.

Turn ignition off. Unplug in-vehicle temperature sensor connector. (Scheme 5) Measure resistance between sensor terminals. See AMBIENT & IN-VEHICLE TEMPERATURE SENSOR SPECIFICATIONS table. Replace sensor if resistance is not as specified.

AMBIENT & IN-VEHICLE TEMPERATURE SENSOR SPECIFICATIONS

Turn ignition off. Disconnect thermal transmitter connector. Using an ohmmeter, measure resistance between thermal transmitter terminal and ground. Resistance should be approximately 70-90 ohms at 140°F (60°C) or 21-24 ohms at 212°F (100°C). If resistance is not as specified, replace sensor.

TRIPLE-PRESSURE SWITCH

1. Connect A/C manifold gauge set. Start engine and turn A/C system on. Disconnect triple-pressure switch harness connector. Triple-pressure switch is located on top of receiver-drier. (Scheme 27)
2. Using an ohmmeter, check continuity between terminals of triple-pressure switch connector as indicated. See TRIPLE-PRESSURE SWITCH SPECIFICATIONS table. Replace switch if it does not test as indicated.

TRIPLE-PRESSURE SWITCH SPECIFICATIONS

Scheme 27

1. Turn ignition off. Disconnect PBR harness connector. Using an ohmmeter, measure resistance between terminals No. 1 (Black/Yellow wire) and No. 2 (Pink/Blue wire) at harness connector. (Scheme 28) Move air mix door lever to coldest position (counterclockwise). With air mix door in full cold position, ohmmeter should indicate zero ohms.
2. Slowly move air mix door lever to hottest position (clockwise). As air mix door motor moves from full cold to full hot position, ohmmeter reading should slowly rise to 3000 ohms. If reading is not as specified, replace air mix door motor.

Scheme 28

Radiator Fan Control

1. Start engine. Turn A/C and blower on. Set controls for maximum cooling. Idle engine for several minutes. If fans operate at low speed, go to next step. If fans DO NOT operate, go to step 3).
2. Turn A/C and blower off. Turn ignition off. Unplug connector from engine coolant sensor, located on top of engine, on left side. Connect 150-ohm resistor across coolant sensor harness connector terminals. Start engine. If fans run at high speed, fan circuits are okay. If fans DO NOT run at high speed, go to step 9).
3. Stop engine. Unplug radiator fan relay No. 1. (Scheme 6) Turn ignition on. Test for battery voltage between ground and relay connector terminals No. 1 and 3. (Scheme 25) If battery voltage exists, go to next step. If battery voltage does not exist, repair wiring as necessary.
4. Unplug connectors from fan motors. Test for continuity between terminal No. 5 of relay connector and terminals "A" and "E" on fan motor harness connectors. (Scheme 29) If continuity exists, go to next step. If continuity does not exist, repair appropriate wire.
5. Unplug ECM harness connector, located in passenger's footwell area. Test Light Green/Red wire for continuity between ECM harness connector terminal No. 14 and terminal No. 2 of radiator fan relay No. 1. If continuity exists, go to next step. If continuity does not exist, repair Light Green/Red wire.
6. Test radiator fan relay No. 1. See «A/C RELAY & RADIATOR FAN RELAY NO»(ref-35561-S14637879262001010900000). 1. If relay is okay, go to next step. Replace relay if defective.
7. Connect positive battery terminal to fan motor terminal "B" or "F" as appropriate. Connect negative battery to fan motor terminal "C" or "G" as appropriate. Fan motor should run smoothly at low speed. If motor runs smoothly at low speed, go to next step. Replace motor if it does not run smoothly.
8. Inspect terminals on ECM and mating harness connector. Repair as necessary.
9. Stop engine. Unplug radiator fan relays No. 2 and 3. (Scheme 6) Turn ignition on. Test for battery voltage at harness connector terminals No. 1 and 3 at each relay. If battery voltage exists, go to next step. If battery voltage does not exist, repair wiring as necessary.
10. Turn ignition off. Unplug fan motor connector. Test for continuity between terminal "B" of fan motor No. 1 and terminal No. 5 of radiator fan relay No. 2 connector. Test for continuity between terminal "F" of fan motor No. 2 and terminal No. 5 of radiator fan relay No. 3 connector. If continuity exists, go to next step. If continuity does not exist, repair appropriate wire.
11. Test for continuity between terminal No. 6 of radiator fan relay No. 2 harness connector and terminal "C" of radiator fan motor harness connector. Test for continuity between terminal No. 6 of radiator fan relay No. 3 harness connector and terminal "G" of radiator fan motor harness connector. Repair appropriate wire if continuity does not exist.
12. Test for continuity between terminal No. 7 of radiator fan relay No. 2 harness connector and ground. Test for continuity between terminal No. 7 of radiator fan relay No. 3 harness connector and ground. Repair appropriate wire if continuity does not exist.
13. Test for continuity between ECM harness connector terminal No. 13 and terminal No. 2 of harness connector for radiator fan relays No. 2 and 3. If continuity exists, go to next step. If continuity does not exist, repair Light Green wire.
14. Connect positive battery terminal to fan motor terminal "B" or "F" as appropriate. Connect negative battery to fan motor terminal "C" or "G" as appropriate. If motor runs smoothly at low speed, go to next step. Replace motor if it does not run smoothly.
15. Connect additional jumper wire between positive battery terminal and fan motor terminal "A" or "E" as appropriate. Connect additional jumper wire between negative battery terminal and fan motor terminal "D" or "H" as appropriate. Fan motor should run smoothly at high speed. Replace motor if it does not run smoothly.
16. If motor runs smoothly at high speed, Inspect terminals on ECM and mating harness connector. Repair as necessary.

Identifying Fan Motor Harness Connector Terminals. Scheme 29

1. Turn ignition off. Using voltmeter, backprobe between terminals No. 35 (Orange wire) and No. 36 (Black/Yellow wire). To vary voltage reading for testing, apply direct sunlight to sensor, then slowly cover sensor.
2. To measure sunload sensor input to auto amplifier, disconnect sensor from vehicle harness above intake unit. Connect an ammeter between sensor connector terminals. To vary current reading, apply direct sunlight to sensor, then slowly the cover sensor. See «SUNLOAD SENSOR SPECIFICATIONS»(ref-35561-S22152223972001010900000) table.

SUNLOAD SENSOR SPECIFICATIONS