1991 BMW 525i One hair puller

Okay have found a diagram and have a something that might be of use to whoever decides to try and help me-

I have narrowed it down to this- after looking at the wire diagram (I can email it to who ever needs to look at it) I wanted to see if I was getting power from the DME to the compressor control relay. so I jumped the #3 to the #5 pin on the relay and whamo I had power to the compressor- BUT still no light on the AC dash control and no cold air.
My question now is this- is it possible to have a bad circuit on the DME in the AC control, and do you think it would be a good idea to buy a DME and try that?
Also according to the diagram I should have a AC compressor control unit in the Left hand kick panel. I removed the panel and there was only a speaker there (I looked behind the speaker and no joy)

So after looking at the diagram again I noticed that it is for a 525i 535i and a M5. I followed the diagram and there is no AC control unit for the 525i only for the M5

I now think since there is a direct line form the DME to the AC compressor Relay that this might be a DME issue.

Any input at all will help

Wow. Let me do a bit of research on that and I will see if there is something to be done from this end. Repost with the last 7 of the vin please.

[quote:60131fa2b5="Dr. Hagerty"]Wow. Let me do a bit of research on that and I will see if there is something to be done from this end. Repost with the last 7 of the vin please.[/quote:60131fa2b5]

BJ66417
1991 525i

DME is a 405

I may be wrong, but the A/C is stand alone on the early production 525. Where was the meltdown and how was it resolved? If you have clutch engagement and no cold air then what are the high and low side pressures? The wiring diagram for your car will be inspected ASAP now that I have the car identified and I will return with an answer no later than Saturday the 10th by 1900 hrs pacific time, ok?

[quote:8730857093="Dr. Hagerty"]I may be wrong, but the A/C is stand alone on the early production 525. Where was the meltdown and how was it resolved? If you have clutch engagement and no cold air then what are the high and low side pressures? The wiring diagram for your car will be inspected ASAP now that I have the car identified and I will return with an answer no later than Saturday the 10th by 1900 hrs pacific time, ok?[/quote:8730857093]

No clutch engagement- No lights on the AC button in the car.
I took a jumper and jumped the #3 to the #5 on the compressor relay and got the clutch to engage but no cold air. this leads me to believe that the DME is the problem.
No power to the compressor relay, no power to the pressure switch (hence no cold air)
The 1991 525i uses the DME for the AC on the #85 pin

That is for the idle compensation for when the A/C is on, not for A/C clutch engagement. If there is power at the climate control, then I would begin to suspect the climate control is compromised, perhaps by the trauma you reported on in an earlier posting.

[quote:343c331708="Dr. Hagerty"]That is for the idle compensation for when the A/C is on, not for A/C clutch engagement. If there is power at the climate control, then I would begin to suspect the climate control is compromised, perhaps by the trauma you reported on in an earlier posting.[/quote:343c331708]

No power to the climate control- I bought a used ECU and it will be here later this week- I'll let you know if that worked.

Installed new ECU (DME) and my AC works- thanks for the help

thanks for the donation