I have a 1993 escort the heat works fine the air doesnt work at a but not worried about that, the fan works on 1 2 and 3 but the whole system shut down when you put the switch on 4. I have replaced the switch and the fan but didn't fix anything any advise from anyone?
Fan switch question on 1993 Ford Escort
by Visitor in Maysville, MO on September 27, 2010
ANSWER by DaveJM , September 27, 2010
Sounds like a blower motor resistor - this is fairly common on this vehicle. Actually, make sure you verify the wiring and connector is ok as well, as they can melt. This vehicle also had a wiring harness issue much further back at the fuel pump, where a jumper harness was installed with a fuse to prevent a short that could melt wiring into the dash and beyond. Not likely to be your issue, but just get a good look at the wiring. The resistor is nearly a 100% fix for your concern.