E36 Compressor not engaging when AC selector switch pressed

[darkislight]

E36 1995 318 convertible Compressor not engaging when AC selector switch pressed.

So, here's the check list:

1. Check the a/c R134a coolant. OK
2. Check the Fuses. OK
3. Check the Relays. OK
4. Check the compressor (bypass the compressor relay). OK
5. Check the pressure switch. OK

Then I see a small green spot of corrosion on the BLK/GRY wire at the pressure switch. The wire is corroded through.

Splice the wire at the corroded section and test. OK

Voila cold air again!!!!

[1823alex]

Check your climate control unit. In my E39 I wasn't able to get the A/C to work until after I swapped the 2003 E39 climate control unit out for a 1998 climate E39 control unit from the scrapyard. Also it sounds stupid but make sure the dial is set to the blue dots and not the red ones.

[dinanstu]

E36 1995 318 convertible Compressor not engaging when AC selector switch pressed.

So, here's the check list:

1. Check the a/c R134a coolant. OK
2. Check the Fuses. OK
3. Check the Relays. OK
4. Check the compressor (bypass the compressor relay). OK
5. Check the pressure switch. OK

Then I see a small green spot of corrosion on the BLK/GRY wire at the pressure switch. The wire is corroded through.

Splice the wire at the corroded section and test. OK

Voila cold air again!!!!

Had ad a similar problem. These older cars start having wires give up, so a good place to look first! Good fix,
enjoy the A/C

[bmwdirtracer]

45 low side is too high. 130 high side sucks. Your expansion valve is clogged, the dryer is toast, and the compressor is likely dying. I suggest you replace all of them.

Proper pressures would be ~30 low side, 200+ high side.