A/C stopped working

Hi w_noel_smith,

You can perform simple checks to understand what could possibly be wrong.

When A/C is turned on, check if the cooling fans are working and the compressor is engaged.

How to Retrieve a Diagnostic Trouble Codes
The Heater Control Panel has a self-diagnosis function. To run the self-diagnosis function, do the following:

1. Turn the ignition switch OFF.
2. Turn the fan switch OFF, the temperature control dial on Max Cool and the mode control dial on Vent.
3. Turn the ignition switch ON (II), then press and hold the recirculation control switch. Within 10 seconds while holding the switch down, press the rear window defogger switch five times. The recirculation indicator blinks two times, then the self-diagnosis will begin. If there is any problem in the system after self-diagnosis is finished, the recirculation indicator will blink the Diagnostic Trouble Code (DTC) 7 through 13. When problems in the evaporator temperature sensor circuit are detected (codes 14 and 15), the A/C indicator will blink the DTC. If no DTC's are found, the indicator will not blink.

Canceling the Self-diagnosis Function

4. Turn the ignition switch OFF to cancel the self-diagnosis function. After completing repair work, run the self-diagnosis function again to make sure that there are no other malfunctions.

Max Cool Position Function

5. When the mode control dial is in the MAX A/C position, the heater control panel will automatically select the Recirculation mode and turn the A/C on. The recirculation switch and A/C switch are disabled and cannot be turned off in this mode. If the control panel fails to function as described, replace it.

DTC 12: A Problem in the Blower Motor Circuit

1. Check the No. 12 (40A) fuse in the under-hood fuse/relay box, and the No. 14 (10A) fuse in the under-dash fuse/relay box.

Are the fuses okay?

Yes - Go to step 2.
No - Replace the fuse(s), and recheck.

2. Connect the No. 2 terminal of the blower motor 2P connector to body ground with a jumper wire.

3. Turn the ignition switch ON (II).
Does the blower motor run?

YES - Go to step 4.
NO - Go to step 17.

4. Turn the ignition switch OFF.

5. Disconnect the jumper wire.

6. Disconnect the power transistor 4P connector.

7. Check for continuity between the No. 2 terminal of the power transistor 4P connector and body ground.

Is there continuity?

YES - Go to step 8.
NO - Check for an open in the wire between the power transistor and body ground. If the wire is OK, check for poor ground at G501.

8. Connect the No. 2 and No. 4 terminals of the power transistor 4P connector with a jumper wire.

9. Turn the ignition switch ON (II).
Does the blower motor run at high speed?

YES - Go to step 10.
NO - Repair open in the wire between the power transistor and the blower motor.

10. Turn the ignition switch OFF.

11. Disconnect the jumper wire.

12. Disconnect the heater control panel 30P connector.

13. Check for continuity between the No. 16 and No. 17 terminals of the heater control panel 30P connector and body ground individually.

Is there continuity?

YES - Repair any short to body ground in the wire(s) between the heater control panel and the power transistor.
NO - Go to step 14.

14. Check the continuity between the following terminals of the heater control panel 30P connector and the power transistor 4P connector.

14.

Is there continuity?

YES - Go to step 15.
NO - Repair any open in the wire(s) between the heater control panel and the power transistor.

15. Reconnect the heater control panel 30P connector.

16. Test the power transistor (see Power Transistor Test ).

Is the power transistor OK?

YES - Check for loose wires or poor connections at the heater control panel 30P connector and at the power transistor 4P connector. If the connections are good, substitute a known-good heater control panel, and recheck. If the symptom/indication goes away, replace the original heater control panel.

NO - Replace the power transistor.

17. Disconnect the jumper wire.

18. Disconnect the blower motor 2P connector.

19. Measure the voltage between the No. 1 terminal of the blower motor 2P connector and body ground.

Is there battery voltage?

YES - Replace the blower motor.
NO - Go to step 20.

20. Turn the ignition switch OFF.

21. Remove the blower motor relay from the under-hood fuse/relay box, and test it (see RELAYS ).

Is the relay OK?

YES - Go to step 22.
NO - Replace the blower motor relay.

22. Measure the voltage between the No. 3 terminal of the blower motor relay 4P socket and body ground.

Is there battery voltage?

YES - Go to step 23.
NO - Replace the under-hood fuse/relay box.

23. Turn the ignition switch ON (II).

24. Measure the voltage between the No. 2 terminal of the blower motor relay 4P socket and body ground.

Is there battery voltage?

YES - Go to step 25.
NO - Repair open in the wire between the No. 14 fuse in the under-dash fuse/relay box and the blower motor relay.

25. Turn the ignition switch OFF.

26. Check for continuity between the No. 1 terminal of the blower motor relay 4P socket and body ground.
Is there continuity?

YES - Repair open in the BLU/WHT wire between the blower motor relay and the blower motor.
NO - Check for an open in the wire between the blower motor relay and body ground.
If the wire is OK, check for poor ground at G301.

Hi Tredick,

It sounds like the system is low on Freon but to be sure lets go over this guide.

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Please run down this guide and report back.

Cheers

Hi Texsman,

What was the low pressure reading?

Possible causes.

1. Excessive refrigerant.
2. Insufficient condenser cooling.
3. Air in system.
4. Faulty expansion valve or heat sensing tube not installed correctly.
5. Restricted lines, check hoses for internal collapsing.

Hi mickys27,

Looks like the control panel is faulty. Internal circuit is missing some power supply. A replacement panel is necessary.

Does the engine run hot if it sits and idles? If not sounds like your AC condenser fan is not working.

You are welcome if the thermostat is good I would be looking at the fan especially with AC shutting off and engine overheating.

Hi HondaOwnerTX,

If the idling system is not working correctly, the compressor cutting in would result in the idling speed dropping. When this occurs, the engine would seem like it is stalling but it would then increase and stabilise again.

Get the IAC and throttle body cleaned and retest.

Actually this is a rather simple job and if you are a DIY guy, it is possible to get it done yourself.

Get a can of carburetor cleaner and a piece of rag.

Remove the air cleaner hose and spry some carburetor cleaner into the throttle body. Spray some into the ports inside the throttle body and let it soak for a while.

Meanwhile use the rag to scrub against the inside of the throttle body, opening the throttle plate manually and get the area where the throttle plate seats at closed position clean.

Starting might be difficult due to the presence of the carb cleaner.

Did you test the blower motor?