Has anyone experienced a ground issue with the a/c relay? My a/c system works perfectly fine if I ground the small yellow wire in the a/c relay located by the hood latch. If it is left grounded permenately by an added ground it has the a/c clutch engaging when the a/c and fans are turned off.

I have the Power FC a/c mod and that works as intended. The a/c system is good with no leaks. Pressure switch is good. This has me confused since all I have to do is touch that wire with a ground and the a/c system works fine.

I did swap the fuel pump and a/c relay to see if that made a difference, but the car started fine and the a/c did not come on. Then again the fuel pump is rewired in the back with a relay so the a/c relay could still be bad. Could the relay be bad or is this a harness/ground issue.

 

this statement is confusing me...what do you mean by "left grounded permanently by an added ground"

your yellow wire is a power wire that is switched when the coil on the relay is powered.

Yellow power wire to relay to B/R wire to magnetic clutch. The magnetic clutch supplies the ground to this wire to complete the circuit.

 

Sorry about the confusion. I noticed that the system wouldn't work until I touched the wire with a ground wire, so I initially tapped that wire and added a ground to see if that would fix the issue. It caused the clutch engagement issue I stated above.

I don't have a schematic and have issues reading them sometimes. I am going from memory here since it is all together and late. There are four wires for that relay. There are two wires that have 12 volts (bigger yellow wire and a black one). Another wire is a black w/ blue wire that goes to the pressure switch, it does not have power when I turn on the a/c in the car. If I ground the smaller yellow wire (not the larger yellow wire) the pressure switch wire receives 12v and the clutch engages. I assumed it was the gound for the relay since it never receives 12v on my test light, but the other three do.

Any ideas?

 

Lets talk this out so I am clear..

Switch on, 12V goes to the coil Blue/Black(wire connected to joint box cigar fuse to ignition) and Yellow/Black wire that grounds through PCM (What I would consider 85 and 86 of the relay)

When that coil has power, Black/Red is switched to Yellow wire (should be the bigger yellow wire you are referring to) (30 and 87 of the relay) activating the magnetic clutch

If you ground that smaller yellow/black wire like you did, you would complete the circuit for the coil and Blue/black would show 12 Volts.

So, I think we are thinking the same....lol

BUT why you have clutch engagement without fans/ac on is stumping me right now...

 

Yes, I believe we are thinking the same! The black/blue wire that goes to the pressure switch only sees power after I manually ground that smaller yellow wire with the a/c on. If I don't ground it that black/blue wire will not have power.

This too has me confused...that is why I am asking!!!

I will take it apart tomorrow and get exact wire colors.

 

only thing I can think of is that you are grounding the small yellow wire and bypassing the PCM so you are bypassing control of the thermoswitch and pressure switch.

 

Do you have a PFC?

 

has a PFC..as stated in the first post Gringo...geez...lol