I've checked the obvious and the archives with no luck. My alternator belt slips especially when lights are on or under load.I've got a new OEM belt with proper tension. Also, the A/C compressor is stuck running even when the swith is off.Could this be the EGI ? Thanks

 

As for the slipping alternator belt ,the adjustment bolt was not holding and let the belt slack off. I put a lock washer behind the bolt and no more screeching.

 

Are you sure the A/C compressor is really running? That would mean your A/C was always on.

 

the AC has a clutch on it that disconnects the pulley from the actual pump when you turn the switch off, if it's always running (your vents are cold all the time when the fan is blowing) than the clutch is bad.

 

Just pull the wire off the ac compressor. Only one wire is there with a disconnect. IF the compressor releases it's clutch, its an elect problem. IF it does not release, then somehow it's a mechanical problem with the compressor.

 

thanks guys. I disconnected the power wire to the compressor and the clutch
disengages so the clutch is okay. I checked the relay and it's okay. If I turn the heat on it works but the A/C compressor is still running. Does it point to the logicon? Everything works ,its just that the a/c is always running even when the
swith is off.

 

How long has this problem existed?

Ever since you owned the car? Or recently?

The reason for asking, is, some people (read previous owner) who can't cut it, so to speak, often make a seperate switch to engage the a/c clutch.

Maybe there is a seperate switch installed by the previous owner, and it's in the ON positon right now.

When you say the ac Main Relay is good, does that mean if you remove the relay, and take a digital meter to it, you cannot read across, or ohm across, the contacts where the Blue/Black wire makes contact, and the where the B/W wire makes contact with the relay. Meaning the relay isn't *stuck*.?

 

JPG Attached of ac stuff.

The way this thing seems to work on a series five, is the Logicon sends a MODE signal to the ECU. IF the ECU sees a a/c signal, it output a ground to the AC Main Relay to pull it in. So it could be a Logicon problem in that it's sending a AC ON signal to the ECU and the ECU is sending a gnd signal to the AC Main relays coil to pull it in and make the clutch in the compressor engage.

I'd go to the ECU and find that pin b/t the ECU and the AC Main relay and see if it's over or under 12vdc. IF under 2vdc, then the ECU is putting a gnd on the relay and pulling it in (probably the case).

It would be pin 1L of the ECU that outputs the gnd to the relay to pull the clutch in. See jpg attached.

I forgot to look at what ECU pin gets the mode signal from the logicon. Maybe later.

EDIT: It's pin 1G, a Blue/Orange (L/O) wire at the ECU that gives the a/c ON signal TO the ECU. Sooooooo...if that pin has 12vdc on it, and the logicon is in ac OFF, then it seeeems the logicon would be the bad actor. Right? Right.

There's a trouble shooting section in the FSM for figuring this out. Sorry, I don't use those until I fail.

 

Here's the one I'd do first. Engine idling and the ac OFF.

Go to pin 1O and backprobe it with a meter. Compare your reading with the jpg attached. That way you can figure out if it's the Logicon or something else.

See if the voltage changes when you put the ac ON or to OFF. Should change. I might have been wrong in something I said about this pin. The logicon puts a ground on the pin 1O. So the voltage seen on that pin should drop when the ac is ON. And rise to approx 12 when ac is OFF.

Then again, previous owner could have installed a switch b/t the logicon and ECU or refigerant switch or who the heck knows.

 

Sounds like a whacky logicon to me.

 

Correction. The second to last post I made is flawed. Not 1G. Should be 1O. Personally I'd do the last post I wrote first. The one where you go to the ECU and backprobe those two wires with the engine at idle and all plugs connected up.

 

thanks. The car was parked over a year but the A/C switch worked before that time. Strange.
I just swapped in another relay and it engaged the compressor.

 

Do you have the ability to get a digital meter and check for the voltage at pin 1O??? That's OH, not zero. One oh.

Meter on ohms, negative lead on a good ground. Positive lead up the back of the wire in 1O. Car idling and all plugs on the ECU and everywhere else. The voltage should rise and fall when you press the ac ON buttom from ON to OFF. Meter should read approx 12v when the ac is OFF and less than 2vdc when ON.

This will prove whether or not the switch in the logicon is working or not. IF you constantly see less than 2vdc even when going on/off with the ac, then most likely the logicon is kaput and locked into ac mode all the time.

The wire color is blue with a orange stripe at pin one OH (1O).

JPG attached is looking into the wire side of the plug on the ECU. Series five.

 

Thanks Hailers, the car broke down so I put in a new ECU. Problem solved