No Power to A/C Clutch?

Topic: No Power to A/C Clutch? (Read 2417 times) previous topic - next topic

No Power to A/C Clutch?

October 31, 2004, 04:37:48 PM

I was trying to fix one problem yesterday with the hesitation, and during it all, another one started. Guess it always goes like that though.

I'm not getting any power to the AC clutch or the diode before it, but there is power at the pressure control switch. The thing thats got me boggled is, if it was a short, wouldn't it blow the fuse? If anyone has had a similar problem, maybe you can help me out. I checked my electrical book in my shop manuals, and it said it might be the blower control switch, but the blower comes on fine. I'm going to try to get it by the dealership tomorrow to see if they can fix it.

Re: No Power to A/C Clutch?

Reply #1 – October 31, 2004, 04:49:49 PM

Matt,

So you know you have power at the pressure control switch , but if you jumper the switch the clutch still doesn't engage? Is that right?

I didn't think there was really anything between the two?

Re: No Power to A/C Clutch?

Reply #2 – October 31, 2004, 04:56:15 PM

We tried jumping the switch and still nothing happened. The problem is so strange...haha I had to take a break from it yesterday cause it was driving me insane. But yes, there is indeed power at the switch.

Re: No Power to A/C Clutch?

Reply #3 – October 31, 2004, 05:17:30 PM

The voltage is fed from the pressure switch to the A/C cut out relay(it is mounted low just in front of the passenger side strut tower). The relay is fed 12v on the red wire and ground is provided by the EEC. So your problem is oone of the following..

1 bad relay(probably)

2 no voltage fed to the relay(on the red wire)

3 wiring problem back to the EEC(orange/Lt Blue wire, if grounding this wire engages the comp, the problem is either #3 or #4)

4 bad EEC(I say thats not really likely but it does happen).

Re: No Power to A/C Clutch?

Reply #4 – November 01, 2004, 08:51:04 AM

I was trying to find the relay yesterday, but I couldn't locate it. I traced the wire down the best I could and wasn't able to spot it. My uncle had mentioned the same thing too (he works at a ford/lincoln dealership) and he said it was probably the relay, but when he couldn't find it he mentioned something about why it didn't have one...I wish I could remember what he said now.

Re: No Power to A/C Clutch?

Reply #5 – November 08, 2004, 05:27:47 PM

My 85 5.0 had the same problem and it turned out to be the blower motor control which has a big heat sink on it and is installed in the fan blower housing. A trace had blown on the controller board which fed power to the low psi cutoff switch then to the a/c clutch. Not sure if the 87s have the same setup.

Re: No Power to A/C Clutch?

Reply #6 – November 11, 2004, 12:16:20 AM

i had the same problem a few years back and it was the relay. i was gonna say that but tom spoke b4 me so. hopefully thats it for you. oh and make sure they give you the rite one i had to go back bc it wasnt rite. ez fix though

Good luck

Re: No Power to A/C Clutch?

Reply #7 – November 11, 2004, 07:16:36 AM

Quote

The voltage is fed from the pressure switch to the A/C cut out relay(it is mounted low just in front of the passenger side strut tower).

Quote

I was trying to find the relay yesterday, but I couldn't locate it.

Is this it?

Re: No Power to A/C Clutch?

Reply #8 – November 11, 2004, 06:58:31 PM

Ummmm, looks like Master Blaster found it with no problem....

Re: No Power to A/C Clutch?

Reply #9 – November 12, 2004, 01:18:01 PM

Yeah it kinda sticks out there all by itself. I had a similar problem with my car right before CJ this past summer. The insulation on the wires was all dryrotted right near the plug that goes into that relay. I had to repair them and when I plugged it back in everything worked fine.