Air Conditioning problem
2001 Honda Civic 4 cyl Two Wheel Drive Manual 83000 miles
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I have a 2001 Civic EX Coupe 5spd and the AC doesnt work. I did some research and came accross similar threads but I didn't find them very helpful for my situation.

Here's what happens: When I press the AC button inside the car, the green light comes on, but the air coming out of the vents is the same temp (really warm). The engine idle remains the same (I saw somebody ask if it increases slightly in another thread). The condenser fan does NOT come on, however if I let the car run a while with the AC on it will spin up for about 15-20 seconds and then stop. I checked all of the related fuses and relays in the fuse box under the hood and the fuse box under the dash and they were fine (I tested the relays with a 12V source).

Also, when the AC is off and I start my car, my radiator fan doesn't spin. The only time I've seen it spin is during that 15-20 second time period when I have the AC on and the condenser fan spins. Then they both stop. Is this normal?

I did the steps to retreive a DTC that I saw posted on another thread and it didn't return anything. The recirculation indicator just turns off and stays off.

Does anybody have any idea what this could be, or what else I should check to help diagnose this problem? I'm kind of a newb (I just got this civic about a month ago) so you might have to tell me where certain things are or what they look like. Thanks!!!

Hi tlabhk,

The radiator fan would not work if the AC compressor is not working or if the fan switch has not been activated, it requires about 15 to 20 mins of runnnig from cold start.

Your compressor don't seem to be working.

If the magnetic clutch relay is faulty, it can cause power to be disrupted.

Test compressor with battery voltage and see if it works.

Thanks. This may be a dumb question, but do you know where the compressor cluth relay is on my civic? I don't see it and I can't find any good diagrams online.

Also, do you know of an easy way of getting to the wires that run to the compressor? There is so much stuff in the way I can barely even see the wires never mind reach them.

Hi tlabhk,

No questions are dumb. It is because we do not know that is why we ask.

Now you are making me dumb I don't have any diagrams of this model and neither do I know of its exact location.

Check the fuse box underhood for the relay. The relays are now indicated with diagrams which I have difficulty deciphering.

If you find the relay, pull it out and test for power to the wire terminals. There should be 1 powered point at all times and 2 when ignition is turned on.

Mark the relays and try swapping them around.

Hey,

You were right, the radiator fan, condenser fan, and compressor clutch relays are all located in the underhood fuse box (I don't think they were like that on 6th gen civics). I tested them all and they all work perfectly fine.

I removed the relays and applied battery voltage to the appropriate slots the relay was sitting in and the condenser fan turned on, the radiator fan turned on, and lo and behold the compressor started spinning! Does this mean that both my compressor and compressor clutch are working and its just a simple fix such as recharging or regasing the system?

What else should I check now that I know the compressor will turn on with direct voltage applied?

Thanks for all your help!

Hi tlabhk,

You haven't replied if there is power supply to the relay terminals.

If no power supply, it could be a blown main (under hood) or under dash fuse

Oh, sorry about that. Yeah, there is one constant power source when the car is off, and two while the car is running at all times to all three of those relays.

Hi tlabhk,

There is power supply so bridge the pressure switch and if the compressor works, it could be the switch or lack of freon in system.

If not, you need to check the activating ground which is from the ECM.

Shorting the pressure switch turns on the condenser fan, radiator fan, and compressor. Is there a way I can test to see if the switch is faulty?

Thanks

Hi tlabhk,

If there is enough freon in the system the pressure switch should have continuity across the 2 terminals.

Test the freon pressure first.