Mechanics

CHEVY AC NOT WORKING

2000 Chevrolet Prizm

Air Conditioning problem
2000 Chevy Prizm 4 cyl Front Wheel Drive Automatic 100000 miles

Last week we had some heavy rains, and I drove through water up to the bottom of my door. Now my AC does not work. The pulley spins but the clutch is not engaging. The light on the dashboard AC button lights OK. I've tested the AC and fan relays and they are all OK.

I do have the Haynes manual.
Avatar
Bclamore
May 9, 2009.



A/C COMPRESSOR CLUTCH DOES NOT ENGAGE

1. Perform HVAC SYSTEM CHECK. Go to next step.
2. Disconnect A/C compressor clutch connector. Connect test light between connector terminals. Start engine and turn A/C to ON position. Turn blower speed selector switch to any position except OFF. If test light illuminates, go to next step. If test light does not illuminate, go to step 4.
3. Replace A/C compressor clutch. After repair, perform HVAC SYSTEM CHECK.
4. Check for open in White/Black wire between A/C compressor clutch, fuse/relay block No. 1, and ground. See WIRING DIAGRAMS. If open is found, go to step 27. If circuit is okay, go to next step.
5. Check for open in Black/White wire between A/C MG relay, fuse/relay block No. 1, and A/C compressor clutch. If open is found, go to step 27. If circuit is okay, go to next step.
6. Reconnect A/C compressor clutch connector. Remove A/C MG relay from fuse/relay block No. 2. Start engine and place blower speed selector switch to any position except OFF. Using DVOM connected to ground, measure voltage at A/C MG relay cavity No. 5. Also measure voltage between A/C MG relay terminal No. 1 and ground. If battery voltage exists, go to step 8. If battery voltage does not exist, go to next step.
7. Repair open in Blue/Red wire between A/C MG relay and fuse/relay block No. 3, or between A/C MG relay terminals No. 1 and 5.
8. Turn ignition switch to LOCK position. Reinstall A/C MG relay. Start engine. Using DVOM connected to ground, measure voltage at A/C compressor control module terminal No. 1 (Yellow/Black wire). If battery voltage exists, go to step 10. If battery voltage does not exist, go to next step.
9. Check for an open in Yellow/Black or Blue/Red wires between A/C compressor control module and fuse/relay block No. 2 (including A/C pressure refrigerant switch). If open is found, go to step 27. If circuit is okay, go to step 28.
10. Check for short to ground in Blue/White wire between underhood Data Link Connector (DLC) terminal No. 8 and PCM connector C-2 terminal No. 15. If this circuit is grounded, vehicle will be in diagnostic request mode and the A/C-heater system will not operate if engine speed is less than 1200 RPM. If short to ground exists, go to step 27. If circuit is okay, go to next step.
11. Turn ignition switch to LOCK position. Reinstall A/C MG relay. Disconnect A/C compressor control module harness connector. Connect fused jumper between ground and A/C compressor control module harness connector terminal No. 9 (Blue/Black wire). Start engine and turn A/C to ON position. Turn blower speed selector switch to any position except OFF. If A/C compressor clutch engages, go to step 14. If A/C compressor clutch does not engage, go to next step.
12. Check for open in Blue/Black wire between A/C MG relay and A/C compressor control module. If open exists, go to step 27. If circuit is okay, go to next step.
13. Replace A/C MG relay.
14. Check for open in White/Black wire between A/C compressor control module and ground. If open is found, go to step 27. If circuit is okay, go to next step.
15. Using DVOM connected to ground, measure voltage at A/C compressor control module harness connector terminal No. 5 (Yellow wire) and ground. If battery voltage exists, go to step 20. If battery voltage does not exist, go to next step.
16. Using DVOM connected to ground, measure voltage at A/C switch harness connector terminal No. 6 (Blue/Red wire). If battery voltage exists, go to next step. If battery voltage does not exist, go to step 19.
17. Check for open in Yellow wire between A/C switch and A/C compressor control module. If open exists, go to step 27. If circuit is okay, go to next step.
18. Replace A/C switch.
19. Repair open in Blue/Red wire between A/C switch and fuse/relay block No. 3.
20. Turn ignition switch to OFF position. Reconnect A/C control module connector. Depress A/C switch to OFF position. Turn ignition switch to ON position. Using DVOM connected to ground, measure voltage at A/C compressor control module harness connector terminal No. 8 (Yellow/Red wire). If reading is 10-14 volts, go to next step. If reading is not 10-14 volts, go to step 24.
21. Start engine and turn A/C to ON position. Using DVOM connected to ground, measure voltage at A/C compressor control module harness connector terminal No. 8 (Yellow/Red wire). If reading is 0-1 volt, go to next step. If reading is not 0-1 volt, go to step 26.
22. Turn engine off. Turn ignition switch to ON position and turn A/C off. Using DVOM connected to ground, measure voltage at A/C compressor control module harness connector terminal No. 3 (Red/Blue wire). If reading is 0-1 volt, go to next step. If reading is not 0-1 volt, go to step 25.
23. Start engine and turn A/C to ON position. Using DVOM connected to ground, measure voltage at A/C compressor control module harness connector terminal No. 3 (Red/Blue wire). If reading is 10-14 volts, go to step 26. If reading is not 10-14 volts, go to step 25.
24. Check for open or short to ground in Yellow/Red wire between PCM and A/C compressor control module. If open or short exits, go to step 27. If circuit is okay, check A/C idle circuit (idle control system).
25. Check for short to ground in Red/Blue wire between PCM and A/C compressor control module. If short is found, go to step 27. If circuit is okay, check A/C idle circuit (idle control system).
26. Replace A/C compressor control module.
27. Repair open or short in suspect wire. 28. Replace A/C refrigerant pressure switch.

***I suspect bad pressure switch***

Tiny
Zackman
May 10, 2009.