G'day,
Here's what I went through to diagnose the same problem in an 89 pickup
the blower motor is up in behind the glove box. You can see it under there and get at it without taking the glove box out. the glove box has to come out to get at the relay. The relay is on the side wall about 5-6inches above the engine control unit (computer).
First rule of thumb, always suspect a relay and I'll bet that is what your problem is. Not common, but if you have nothing it is either the blower motor itself or the relay or the heater fuse which is below the heater (blower) relay.
I popped the blower motor completely out and ran 2 wires to it from the battery, it shows you the positive and negative terminals on the blower connections. That'll let you know if that is working or not. Next check the fuse, it should be alright unless there is a bad ground somewhere.
Whilre you are in there, the blower resistor is the thing that is in the way of getting the blower motor out, you may have to pull the wiring harness off it to get the blower motor out. Drop the 2 screws and pull it out to see if the resistors are fine. if you loose fan level 1 2 or 3, it indicates one of the resistors is blown and you may need a new resistor if it matters to you ($33 OEM)
the relay was $28 OEM, blower switch itself is $70+/- but if the blower/heat panel backlight works, your switch is likely alright.
HOW TO TEST THE RELAY: If the blower motor works, take the relay out. there are 5 terminals, 3 smal ones in a row, and 2 big ones below that. cross a wire between the 2 big ones, that should make the blower motor work even with the key out if your switch and motor are good. test it on high. high blower fan speed bypasses the resistor and sends full power through the resistor terminal.
My pain can hopefully be your gain !! I knew none of this 2 weeks ago
Sidney helped me out !
Pete
no problem
Linear Mode
