2001 BMW 530i has no check engine light code but AC does not work?

Vehicle Problem:

I am a member of ATS and my BMW 530i has no AC. As per your instruction regarding resetting the AC control unit, I removed the battery terminals and joined them together but still my AC does not work. Also, when I checked the control unit, it does not send power to the compressor clutch. I had a garage get the code for me and they found none. What do I do?

Vehicle Question Answer:

To give you some basic principle on your AC, your controller controls your AC compressor by supplying power to your compressor clutch. It does this after reviewing all the inputs like engine speed, freon temp and pressure, etc. To check, make sure there is power and ground going to the control unit. Then check if the control unit is sending power to the clutch wire after you turn it on. Sometimes, the control unit needs resetting and you can do it by touching the battery terminals together at least 30 minutes. This should wake up the sleepy controller and you can verify that by checking the clutch wire again.

You need a wiring diagram to fix this so you can identify the wires involved. ATS will supply it to you if you ask for it.