AC weirdness

[Jaybee325is]

My A/C fan motor will come on while in cranking my car but turns off after I let off the ignition. Relay? Corrosion?
Also my tach is acting wonky (works sometimes) heat gauge doesn't work. Not stressed out about either. Just don't know if there's a relationship.

[jlevie]

The tach & temp gauge are probably problems in the instrument cluster. I have no idea why the aux fan would turn on while cranking.

[Jaybee325is]

Should have been more clear. I'm trying to get the fan to work. The fan is in the on position. It just cuts out after I let off because the car is cranked.

[jlevie]

What car is this? The operation of the aux fan is different between early and late models.

[Jaybee325is]

88 325ic

[jlevie]

Okay, that means the car should have a three terminal starter. One of the terminals operates the unloader relay, which should prevent the HVAC system, aux fan, and windows from running when cranking. Diagnostic work is going to be required to find/fix the problem. The factory wiring diagrams (http://wedophones.com/BMWManualsLead.htm) will help.

[Jaybee325is]

I'll check it in the AM. Thanks!

[M_3_X]

My A/C fan motor will come on while in cranking my car but turns off after I let off the ignition. Relay? Corrosion?
Also my tach is acting wonky (works sometimes) heat gauge doesn't work. Not stressed out about either. Just don't know if there's a relationship.

Just for clarification, are you referring to the a/c blower motor or the aux fan in the engine compartment?
I see there might be some confusion going on.