Help fix AC electrical issue

[tjts1]

I'm in the process of bringing my AC back to life. Thankfully it holds pressure, lots of it in fact but it won't turn on. When I press the AC button, light turns blue, aux fan activates but the AC clutch doesn't engage. I'm not getting voltage to the AC clutch. I hotwired the AC clutch to run off the low beam for a test. With power from the headlight, clutch engages and Immediately the temp at the vents starts drop all the way down to 46F with 80F ambient temp. So the mechanical side of the AC is solid. I have an electrical problem somewhere between the switch and the clutch. Fuse is good, the AUX fan kicks in but theres no voltage to the clutch. The electrical diagrams are not very detailed. I don't even know where most of these components are located. Where do I begin. Any imput is welcome. Heres the diagrams I'm working with. The car is a 91 318i.

Where is the "A/C compressor control unit" located? That would be a good start.


Part of the AUX fan diagram dealing with the AC.


Thanks for the help
Justin

[lordofthewaters]

I had this same problem last year, and never found the culprit. I ended up running back to another button that I installed in the console to get A/C on hot days.