You might do a couple of tricks, 1) Take a piece of jumper wire, go to front of car, under bumper, behind grill, and find a 1/2X1/2X3 inch ceramic box with two large wires soldered at each end. Take jumper wire, jumper across the terminals and see if fan works when A/C selected, if fan works, then you need to replace resistor you just jumpered across, or soler in jumper and have super cool A/C; 2) locate the Normal speed relay and High speed relay and swap the two relays, does fan work w/A/C? if it does, replace other relay swapped. If fan does not work, check fuse, and see Step 1.

Everett 88 325iC -- Need more power, Scotty!!!

Here is my question, should the auxiliary fan turn on as soon as you turn on your A/C?
Or does it only turn on when A/C runs for a while. Thanks for any help.
91 318is
Art