Recently the blower motor in our 1990 Ranger has stopped blowing regardless of the position the switch is in. We've checked the fuse and it's alright, but I'm wondering what else there is to check before ruling that it is the motor itself that is bad? Hoping for a relatively simple fix, simply because we're expecting triple-digit temperatures in the upcoming week.

 

If you have a circuit tester you could check resistance of the motor itself. You could also use a jumper wire to bypass the rest of the circuit and see if you can get it to run.

 

The blower motor wiring connector should have two wires, one should be Pink with a White stripe and the other should be Orange with a Black stripe. If this is correct, check the following:

At the blower motor electrical connector, utilizing either a test light or voltmeter, back probe the Pink with White stripe wire at the connector with the key on and the blower switch set to high speed and the selector control set to panel (dash vents). You should have power.

If you have power in above, insert a jumper wire connected at one end to a known good ground and the other end into the connector side with the Orange with Black stripe wire. The motor should run. If not, either the blower motor is bad or the blower motor relay may be faulty (see below)

If you did not find power in the above, you’ll need to locate the Blower Motor Relay. Remove the relay and insert a jumper between the socket terminals 3 and 5 and retest the system. If the blower motor now works normally (all fan speeds), pull the jumper wire and test socket terminal 1 with an Ohmmeter to ground. Should read less than .5 ohms. If so, replace the relay. If not, either the selector control switch or its ground is bad.

 

Glad you went indepth...I didn't want to type that much. Another very easy thing to try is turn the fan on and give it a tap or kick.

 

I think that method requires one of those special dealer only thumpers or you'll void your extended warranty