A/C Compressor Clutch not Engaging
 

OKay so i got a 01 civic ex sedan, and the compressor went bad last week. So i replaced it with one i had bought from a local seller on craigslist (supposedly he ordered it online and later found out he didnt need it). Well i got the new one on and charged it up and the compressor clutch will not engage. I tested the signal wire that goes to the compressor and it gets power when you press the ac button inside the car. SO i know its not an electrical issue. The fans come on and rpm rises a bit as well, so i know its not the pressure switch either. Any Ideals?

Re: A/C Compressor Clutch not Engaging
 

anyone??? im starting to think its a defective compressor

Re: A/C Compressor Clutch not Engaging
 

Check for any HVAC DTC's.

I'll scribble something together in the next day or two for troubleshooting the A/C compressor clutch circuit.

Re: A/C Compressor Clutch not Engaging
 

Okay ill do the diagnosis process. N ill wait for ur info on the clutch circuit . Thanks for the help!

Re: A/C Compressor Clutch not Engaging
 

how do i check the ac compressor clutch clearance, the thermal protector, and the A/C compressor clutch field coil?

Re: A/C Compressor Clutch not Engaging
 

will try ur last set in instructions...if that doesnt do it, im probably gonna start swapping parts over from my old compressor, or ill just order a new one online.

Re: A/C Compressor Clutch not Engaging
 

it was the relay on 2 of mine

Re: A/C Compressor Clutch not Engaging
 

but the thing is that the wire at the compressor has +12 power, so it cant be an electrical issue.

Re: A/C Compressor Clutch not Engaging
 

i'm no expert, but just because it has voltage going to it, doesnt mean it should work. if there is a disconnection beyond that point which prevents the circuit from connecting to ground, it wont work and it would be an electrical issue. (in case you haven't, its important to go through every step mentioned above, starting with the note)

Re: A/C Compressor Clutch not Engaging
 

The wire im checking for voltage is the wire at the compressor. Theres no wires beyond it. When i turn the ac button on the compressor wire get +12 meaning all the relays and fuses are working properly which have provided the compressor with power. Therefore it cant be an electrical issue with the fuses or relays. The only thing i can see it being is the ac compressor clutch clearance, the thermal protector, or the A/C compressor clutch field coil?

Re: A/C Compressor Clutch not Engaging
 

and this thing is so cramped, the only way i could properly inspect everything is by removing the p/s and alternator. And at this moment im considering just replacing the compressor as im already removing everything in my way to get the replacement in

Re: A/C Compressor Clutch not Engaging
 

Thanks for the trouble shooting steps. I followed them and found the trouble - a bad compressor relay. I replaced it and AC is working great. Yo saved me a couple of hundred dollars!

Re: A/C Compressor Clutch not Engaging
 

Why is "measure the voltage between the #18 terminal (red wire) of ECM/PCM connector E and a body ground with the ECM/PCM connectors connected" considered bad in the circuit? Is that preventing the path to ground from happening? My car does show a voltage of 11V at this point and my AC doesn't engage (light turns on at the console switch but nothing happens) and both fans work when the engine is hot.

I measured and checked everything is good with the AC (battery voltage at the relay, relay clicks under manual test, swapped it with other relays, fuses are good) but the AC doesn't work unless I jump the relay at the socket. I don't have a pressure tester but the pressure switch is showing shorted which means at least the static pressure has to be somewhere in the okay region.

I have a 2003 Civic Coupe Si (Canadian model). The original ECU died and it was replaced with an identical unit from a junkyard front-end collision and re-programmed by the Honda dealer.

What else could be wrong? Before I go and buy another ECU and have that one re-programmed just for a $200-$300 test :mad:

Re: A/C Compressor Clutch not Engaging
 

My a/c unit is no longer working too, after an engine swap. While researching someone mentioned that some a/c units auto shuts off and won't kick in if there is no freon.

Re: A/C Compressor Clutch not Engaging
 

Yes that's true but if you check the pressure switch is shorted with an ohm meter it means that the pressure is at least good in a rudimentary way. If it is open then it means that there is no gas or too much gas.

When I do the HVAC self test I don't get any errors either but the strange thing is that the AC light doesn't come on during the test. So that means that it thinks that my car is not equipped with AC. So I can only assume that means that the ECU/HVAC controls I have don't think there is any AC or there is some other strange issue that causes it not to recognize the AC :mad:

Re: A/C Compressor Clutch not Engaging
 

After Honda troubleshot the AC for me they determined that the thermal protect circuit is bad. It's too cold outside to short it out and bypass it so it'll have to wait until the spring/summer to look into it further.

Re: A/C Compressor Clutch not Engaging
 

I have read a number of topics on this. It sounds like your high pressure "RELAY SWITCH" is working. Now this also depends on the yr. and such but in your "Primary Fuse Block" under the hood there will be a "AC" relay block, if your system is so low on your charge this relay refuses to let your compressor come on. Now there is a way to take this relay fuse block out and jumper with a paper clip to make your compressor to come on. Now here's where I'm no help and seeking this myself there are four slots to this relay. Now the Two main slots you can meter (ohm) out and it will show the contact closed. If you pull this block and then meter under (DC) you can find the power side where the block plugs into. (Power must be on (AC), but engine doesn't have to be running) The problem that I'm having myself is I don't know which of the other two slot's to jumper too. If you get the right one you don't even have to have the ac switch on in the vehicle (when running), your compressor will come on and then it can receive a charge. I'm just to chicken to try either post, want the correct one because I fear destroying something else if I connect it to the wrong slot. If someone out there knows this answer please share. For all I know ALL (AC) relay blocks maybe the same on Honda's. I've looked but haven't found the answer myself yet. Hope this help's.

Re: A/C Compressor Clutch not Engaging
 

Hi williamt2008, Here's how I think it can work if you want to try jumping the relay. First take the relay out with the car running and A/C off. With your volt meter grounded to the negative terminal of the battery check that each of your 4 connectors in the relay slot register zero volts. Now turn the A/C switch ON and check again. One of them should have power now and the others will not. Now you can make a 6 inch or so jumper wire with bare ends. Connect one to the hot plug you identified above and the other to the relay lug that feeds the compressor.
I am not a mechanic and I have not tested this on your year or make car so take it for what it is worth. Regards.

Re: A/C Compressor Clutch not Engaging
 

Low freon will cause a clutch to not engage. Fill and add dye. Check for leaks.

Re: A/C Compressor Clutch not Engaging
 

What is ohms reading AC compressor coil in 2006 civic