BLOWER MOTOR WON'T RUN
- Check for blown fuse.
- Turn ignition switch to "RUN" position and check for voltage at function control switch.
- Switch blower selector to "HI" position and check for voltage at switch and at high speed blower relay.
- Ground blower motor with ignition switch in "RUN" position.
BLOWER DOES NOT OPERATE IN "HI"
Check for voltage at high speed blower relay with ignition switch in "RUN" position and blower switch in "HI" position. If not okay, check for voltage at blower switch.
BLOWER OPERATES ONLY IN "HI"
Check blower resistors for open condition.
BLOWER OPERATES IN "HI" WITH IGNITION SWITCH "OFF"
INSUFFICIENT COOLING "QUICK-CHECK" PROCEDURE
This procedure may be used to determine whether or not the A/C system has the proper refrigerant charge. Ambient air temperature must be above 70°F (21°C). It can eliminate an entire system checkout.
- Start engine and bring to normal operating temperature. Ensure engine is at normal idle speed. Open doors and engine hood (trunk on Fiero models). Set function lever to "NORM" position, temperature lever to "COLD" position, and blower on "HI" position.
- "Hand-feel" the temperature of the accumulator surface AND the evaporator inlet pipe while the compressor is engaged. It is normal for the compressor to cycle on and off to meet system requirements. If the accumulator surface and evaporator inlet pipe are the same temperature, and slightly cooler than ambient air, system is normal.
- If inlet pipe is frosted or feels cooler than accumulator surface, then add refrigerant in 4 oz. increments, allowing system to stabilize between additions, until both feel same temperature. Add 14 oz. more refrigerant.
INSUFFICIENT COOLING "THOROUGH CHECK" PROCEDURE
Note. CCOT system is not equipped with a sight glass, and under no circumstances should a sight glass be installed.
- To thoroughly check refrigerant system, attach manifold gauge set, and refer to Insufficient Cooling Chart on the following pages. Note that compressor clutch cycles on and off during normal operation.
- When using Insufficient Cooling Chart, note that minor variations occur in cycling pressures, but otherwise procedures apply to all models.
- In checking cycling of clutch on various models, it may be necessary to connect a jumper wire to terminals and leads of various cut-off switches and relays in order to check system fully.
VACUUM SYSTEM DIAGNOSIS
- With engine idling, move mode selector lever to each position. Refer to appropriate vacuum diagram in MANUAL A/C SYSTEM article for proper airflow, air door functioning, and vacuum circuits.
- If airflow is not as shown in operational charts, check vacuum hose connections at actuators, control head valve, reservoir, tees, etc.
- Check vacuum source circuit by installing tee and gauge (with restrictor) at vacuum outlet. Refer to appropriate vacuum diagram in MANUAL A/C SYSTEM article.
- Idle engine. Vacuum should be equal to engine vacuum in all selector positions. If vacuum is less than normal in all positions, remove tee and connect gauge line directly to tank.
- If vacuum is still low, problem is in feed circuit. If vacuum is normal, problem is downstream. If vacuum is less than normal in some selected positions, leak is in these circuits.
- If vacuum was normal and even at all positions, malfunction is probably caused by improperly connected lines, plugged lines, or defective vacuum valve(s).
- To check a specific vacuum circuit, place mode selector lever in the position where malfunctioning occurred. Check for vacuum at the affected actuator. If vacuum exists, but door does not move, actuator is defective or binding.
- If low or no vacuum exists at the actuator, determine whether vacuum harness or vacuum valve is faulty. Check vacuum harness first.
OPERATIONAL TESTING
When trouble shooting and diagnosing an air conditioning system, always refer to the appropriate vacuum and wiring diagrams in MANUAL A/C SYSTEM article for the system involved. Refer to the applicable operational chart for characteristics. In general
- Blower operation at all speeds and engagement of the compressor clutch would indicate that electrical circuits are functioning properly.
- If evaporator inlet pipe and accumulator surface both appear to be the same temperature when felt by hand, system is properly charged with refrigerant.
- Operation of mode selector lever to distribute air from designated outlets would indicate proper vacuum and diaphragm function.
AIR CONDITIONER DOESN'T WORK
Note. To check Celebrity, Citation II with 2.5L or 2.8L engine, Pontiac Fiero with 2.5L engine or 2000 with 1.8L EFI, 1.8L Turbo or 2.0L EFI engine, see appropriate ECM Controlled Test Table in this article.
- With engine running and mode lever at "NORM" position, check for voltage at pressure cycling switch.
- Check for voltage between pressure cycling switch and compressor clutch.
- Ground compressor clutch circuit. If clutch engages, check wide-open throttle cut-out switch and A/C compressor cut-off switch.
Insufficient Cooling. Scheme 10
Scheme 10: Insufficient Cooling
Insufficient Cooling. Scheme 11
Scheme 11: Insufficient Cooling
| TEST POINT | TEST FOR | CONDITIONS |
|---|
| Brown Wire | 12V | A/C feed and A/C fuse OK. |
| Lt Green Wire | 12V | A/C controller in "Max", "Norm", "Bi-Level" or "Def" mode |
| Lt Blue Wire Dk Green/White Wire | 12V Check at terminal B of A/C control relay | Pressure cycling switch closed (above approximately 45 psi). |
| ECM Terminal No. 21(Wht connector) | 12V | Pressure cycling switch closed (above 45 psi). Absence of 12 volts on this circuit can result in no A/C "On" signal for idle speed increase (See note below). |
| Pink/Blk Wire | 12V Check at terminal A of A/C control relay | Gage feed and gage fuse OK |
| (1) Make the following tests with ignition "On", engine "Off" and A/C controller in "Norm". |
| (1) | Make the following tests with ignition "On", engine "Off" and A/C controller in "Norm". |
ECM CONTROLLED TEST (CELEBRITY & CITATION II WITH 2.5L ENGINE) ()
| TEST POINT | TEST FOR | CONDITIONS |
|---|
| Dark Blue Wire (2) | Continuity to ECM terminal 7 (black connector, relay solenoid ground). | ECM de-energizes relay during wide open throttle, low idle speed (See Tune-Up Label) or high-power steering loads. |
| Dk Green/ White Wire | 12V | Compressor control relay energized by ECM (relay solenoid energized by ground through terminal No. 7). |
| Black Wire | Continuity to ground through high pressure cut-off switch. | High pressure cut-off switch closed (below 200 psi). |
| (1) Make the following tests with engine running. A/C controller in Norm and pressure cycling switch connector terminals jumpered prolonged running on this mode may result in high pressure cut-off switch off compressor). (2) If compressor control relay can be energized only by connecting jumper from terminal C of relay to ground and circuit 458 checks OK, problem is ECM related circuits throttle position sensor - wide open throttle signal; tachometer signal - low idle speed; or, power steering pressure switch - high pressure signal). |
| (1) | Make the following tests with engine running. A/C controller in Norm and pressure cycling switch connector terminals jumpered prolonged running on this mode may result in high pressure cut-off switch off compressor). |
| (2) | If compressor control relay can be energized only by connecting jumper from terminal C of relay to ground and circuit 458 checks OK, problem is ECM related circuits throttle position sensor - wide open throttle signal; tachometer signal - low idle speed; or, power steering pressure switch - high pressure signal). |
ECM CONTROLLED TEST (CELEBRITY & CITATION II WITH 2.5L ENGINE) (2)
| TEST POINT | TEST FOR | CONDITIONS |
|---|
| Brown Wire | 12V | A/C feed and A/C fuse OK. |
| Lt Green Wire | 12V | A/C controller in "Max", "Norm", "Bi-Level" or "Def" mode. |
| Dk Green Wire To Wide Open Throttle Relay Check at Relay Terminal E | 12V | Pressure cycling switch closed (above 45 psi). |
| Pink/Blk Wire Check At Relay Terminal C | 12V | ECM feed and ECM fuse OK. |
| Brown Wire (2) | Continuity to ECM terminal 6 (relay to solenoid ground). | ECM de-energizes relay during wide open throttle cutting-off compressor. |
| Dark Green/ White Wire | 12V | Wide open throttle relay energized by ECM (relay solenoid energized by ground through terminal 6). |
| Dark Green Wire | 12V | Power steering cut-off switch closed (below 350 psi). |
| Black Wire | Continuity to ground through high pressure cut-off switch. | High pressure cut-off switch closed (below 200 psi). |
| (1) Make the following tests with ignition "On", engine "Off", and A/C controller in "Norm". (2) If wide open throttle relay can be energized only by connecting jumper from terminal B of relay to ground and circuit 449 checks OK, problem is ECM related circuits (throttle position sensor - wide open throttle signal). |
| (1) | Make the following tests with ignition "On", engine "Off", and A/C controller in "Norm". |
| (2) | If wide open throttle relay can be energized only by connecting jumper from terminal B of relay to ground and circuit 449 checks OK, problem is ECM related circuits (throttle position sensor - wide open throttle signal). |
ECM CONTROLLED TEST (CELEBRITY & CITATION II WITH 2.8L ENGINE) (1)
| TEST POINT | TEST FOR | CONDITIONS |
|---|
| Brown Wire Term "N" A/C Controller. Term "D" A/C Control Relay. | 12V | A/C feed and A/C fuse OK. |
| Brown Wire at Press. Cycling Switch Conn. | 12V | A/C controller in "Max", "Norm", "Bi-Level" or "Def" mode. A/C controller OK. |
| Light Blue Wire Term "21" White ECM Conn. Term "A" A/C Control Relay. | 12V | Pressure cycling switch closed (above 45 psi). Absence of 12 volts on this circuit can result in no A/C "On" signal for idle speed increase (See note below). |
| (1) Make the following tests with ignition "On", engine "Off", and A/C controller in "Norm". |
| (1) | Make the following tests with ignition "On", engine "Off", and A/C controller in "Norm". |
ECM CONTROLLED (FIERO WITH 2.5L ENGINE) (1)
| TEST POINT | TEST FOR | CONDITIONS |
|---|
| Dark Blue Wire (2) | Continuity to ECM terminal No. 7-black conn. (relay solenoid ground). | ECM de-energizes relay during wide open throttle and low idle speed (See Tune-Up Label for idle speed). (See note below.) |
| Dk Green Wire | 12V | Compressor control relay energized by ECM (relay solenoid energized by ground through terminal No. 7). (See note below). |
| Black Wire | Continuity to ground through high pressure cut-off switch. | High pressure cut-off switch closed (below 200 psi). |
| (1) Make the following test with engine running. A/C controller in "Norm" and pressure cycling switch connector terminals jumpered (prolonged running in this mode may result in high pressure cut-off switch turning off compressor). (2) If compressor control relay can be energized only by connecting jumper from terminal "C" of relay to ground and circuit 458 checks okay, problem is ECM related circuits (throttle position sensor - wide open throttle signal; or, tach signal - low idle speed). If compressor control relay can NOT be energized by grounding terminal "C" of relay and circuits 50 and 67 check OK, check resistance between relay pins "1" and "3". If over 20 ohms, problem is ECM connections or ECM. If less than 20 ohms, solenoid coil has shorted - replace relay and ECM. |
| (1) | Make the following test with engine running. A/C controller in "Norm" and pressure cycling switch connector terminals jumpered (prolonged running in this mode may result in high pressure cut-off switch turning off compressor). |
| (2) | If compressor control relay can be energized only by connecting jumper from terminal "C" of relay to ground and circuit 458 checks okay, problem is ECM related circuits (throttle position sensor - wide open throttle signal; or, tach signal - low idle speed). If compressor control relay can NOT be energized by grounding terminal "C" of relay and circuits 50 and 67 check OK, check resistance between relay pins "1" and "3". If over 20 ohms, problem is ECM connections or ECM. If less than 20 ohms, solenoid coil has shorted - replace relay and ECM. |
ECM CONTROLLED (FIERO WITH 2.5L ENGINE) (1)
| TEST POINT | TEST FOR | CONDITIONS |
|---|
| Brown Wire | 12V | A/C feed and A/C fuse OK. |
| Blk/Light Blue Wire | 12V | A/C controller in "Max", "Norm" "Bi-Level" or "Def" mode. |
| Dk Green Wire To Compressor Control Relay. Check at Relay Terminal E. | 12V | Pressure cycling switch closed (above 45 psi). |
| ECM A/C "On" Input Terminal. Dk Green/White Wire (CKT 459) | 12V | Pressure cycling switch closed (above 45 psi). Absence of 12 volts on this circuit can result in no A/C "On" signal for idle speed increase (See note below). |
| Pink/Blk Wire Check at Relay Terminal C | 12V | Gage feed and gage fuse is okay. |
| (1) Make the following tests with ignition "On", engine "Off", and A/C controller in "Norm". |
| (1) | Make the following tests with ignition "On", engine "Off", and A/C controller in "Norm". |
ECM CONTROLLED (PONTIAC SUNBIRD WITH 1.8L EFI OR 1.8L TURBO ENGINE) (1)
| TEST POINT | TEST FOR | CONDITIONS |
|---|
| Dark Blue Wire (2) | Continuity to ECM compressor control relay terminal (relay solenoid ground). | ECM de-energizes relay during wide open throttle and low idle speed (See Tune-Up Label) |
| Dk Green Wire | 12V | Compressor control relay energized by ECM (relay solenoid energized by ground through terminal). |
| Black Wire | Continuity to ground through high pressure cut-off switch. | High pressure cut-off switch closed (below 200 psi). |
| (1) Make the following tests with engine running, A/C controller in "Norm" and pressure cycling switch connector terminals jumpered (prolonged running in this mode may result in high pressure cut-off switch turning off compressor). (2) If compressor control relay can be energized only by connecting jumper from terminal C of relay to ground and circuit 458 checks okay, problem is ECM related circuits (throttle position sensor - wide open throttle signal; tachometer signal - low idle speed; or, power steering switch - high pressure signal). |
| (1) | Make the following tests with engine running, A/C controller in "Norm" and pressure cycling switch connector terminals jumpered (prolonged running in this mode may result in high pressure cut-off switch turning off compressor). |
| (2) | If compressor control relay can be energized only by connecting jumper from terminal C of relay to ground and circuit 458 checks okay, problem is ECM related circuits (throttle position sensor - wide open throttle signal; tachometer signal - low idle speed; or, power steering switch - high pressure signal). |
ECM CONTROLLED (PONTIAC SUNBIRD WITH 1.8L EFI OR 1.8L TURBO ENGINE) (1)
| TEST POINT | TEST FOR | CONDITIONS |
|---|
| Brown Wire | 12V | A/C feed and A/C fuse OK. |
| Blk/Lt Blue Wire | 12V | A/C controller in "Max", "Norm" "Bi-Level" or "Def" mode. |
| Dk Green Wire Dk Green/Wht Wire To Compressor Control Relay Check at Relay Terminal E | 12V | Pressure cycling switch closed (above 45 psi). |
| ECM Terminal (Terminal B8 Dk Green/Wht Wire | 12V | Pressure cycling switch closed (above 45 psi). Absence of 12 volts on this circuit can result in the A/C control relay remaining de-energized (See note below). |
| Pink/Blk Wire Check at Relay Terminal C | 12V | Gage feed and gage fuse is okay. |
| (1) Make the following tests with ignition "On", engine "Off", and A/C controller in "Norm". |
| (1) | Make the following tests with ignition "On", engine "Off", and A/C controller in "Norm". |
ECM CONTROLLED TEST (PONTIAC SUNBIRD WITH 2.0L EFI ENGINE) (1)
| TEST POINT | TEST FOR | CONDITIONS |
|---|
| Lt Blue Wire (2) | Continuity to ECM terminal 7 (black connector, relay solenoid ground). | ECM de-energizes relay during wide open throttle and low idle speed (See Tune-Up Label) |
| ECM Terminal C8 Gray Wire | 12V | A/C control relay energized. Absence of 12 volts on this circuit can result in idle degradation (See note below). |
| Gray Wire | 12V | Compressor control relay energized by ECM (relay solenoid energized by ground thru terminal). |
| Purple Wire | 12V | Power steering cut-off switch closed (below 350 psi). |
| Black Wire | Continuity to ground through high pressure cut-off switch. | High pressure cut-off switch closed (below 200 psi). |
| (1) Make the following tests with engine running. A/C controller in "Norm" and pressure cycling switch connector terminals jumpered (prolonged running in this mode may result in high pressure cut-off switch turning off compressor). (2) If compressor control relay can be energized only by connecting jumper from terminal B of relay to ground and circuit 905 checks okay, problem is ECM related circuits (throttle position sensor - wide open throttle signal; or, tachometer signal - low idle speed). |
| (1) | Make the following tests with engine running. A/C controller in "Norm" and pressure cycling switch connector terminals jumpered (prolonged running in this mode may result in high pressure cut-off switch turning off compressor). |
| (2) | If compressor control relay can be energized only by connecting jumper from terminal B of relay to ground and circuit 905 checks okay, problem is ECM related circuits (throttle position sensor - wide open throttle signal; or, tachometer signal - low idle speed). |
ECM CONTROLLED TEST (PONTIAC SUNBIRD WITH 2.0L EFI ENGINE) (1)
