Yep... Shorting the wires will force the fan to come on, just like a high pressure on the drier (consult the wiring diagram), but this does not prove the fan will function properly. Shorting the wires together does prove the relay for the A/C drier pressure is functional if the fan comes on, and it also proves the resistor is not open.

I suspect an aux fan relay is faulty in the OP's post. Otherwise, wiring is suspect. Since he jumped the contacts on the temp switch and the fan did not run, I suspect the relay. The fan will work independent of the A/C circuit (once again, consult the wiring diagram), and vice-versa. The two circuits are essentially separate. The A/C pressure switch routes the voltage thru the resistor, but the temp switch does not.

And according to recent discussion on another board, if you do change the switch on the drier, you will vent freon...

Question: When do you expect the auxilary fan to be on?

__________________
RM Smith
1988 560SL

"Where is it again that we are going, and why are we in this handbasket"?