Got a bit of a head scratcher on this one for you more experienced mechanics...

My blower fan isn't working. Checked the usual first culprit, the resistors, ad they're good. Threw in a new unit for good measure, and still no dice. Not the first time this has happened, and it's been the speed selector switch once and the resistor block another time.
The really odd part is that it will occasionally restart after hitting a bump in the road just right, only to die out after another road bump.

Any thoughts?

 

I just through these steps today as my fan cut out yesterday




You'll need a voltmeter and jumper wires to troubleshoot though. Three wires with alligator clips on both ends should be all you really need.


If you don't understand the above, here are the steps.

1) Check your fuse, should be a 30A underneath your steering column.

2) Pull 2 wire connector right underneath blower motor, check blue-white for 12+V when ACC is on.

3) Make a bridge between the two-wire connectors, use third wire to make a connection to chassis ground and to connect to blue-black wire.


If it works, there is a break between blue-black and a ground source (probably a bad speed control switch)


If it fails, you have a dead/dying motor (since you already replaced the resistor)


Mine ended up being the speed control switch/slider. There are a couple of spring loaded contacts in there, one of them got pinched and it stuck in a position that stopped making contact with the circuit.

 

Thank you much for the advice, boibuddha. Once it stops raining for a few hours here in Seattle, I'll run out and do the checks.

 

Found the fault...





How that didn't catch fire is beyond me. But, that's an easy fix. One trip to the local Pick'n'Pull with a pair of diagonal cutters coming up!

 

Thanks for the posting your findings.

At least you didn't have to tear apart your dash to find it. Even then though, its like 4 screws for us EF guys.

When you do replace that crispy wiring, remember to solder the wires together.

With all the vibrations from the blower motor and driving itself, twisted wires can come apart and start burning up your wiring again as current is forced to go through fewer and fewer strands as they let go.

 

Wire nuts or other twisting connections was never an option in my books. However, my dad raised a good point: what caused this connection to get cooked? Perhaps I need to jumper across this section and see if the motor is bad...

 

Was that connector in an area that could have gotten wet?

 

Tyson, That connector is found in the passenger footwell area, about 6 from the blower motor itself.

From the looking at the pictures, the frayed wiring seems to be the culprit here. Almost looks like someone pulled back on the wiring to create an access point for a multimeter or damage caused by trying to pull connectors apart.

The heat seems to be focused on the hot side of the connection, blue-black and red. The narrower frayed path there would cause excessive heat to build up. Technically, an aftermarket resistor could cause wiring to burn up too but then the damage would be consistent everywhere along that circuit.

 

yeah likely. the copper green corrosion seemed odd to me tho. glad you found your culprit.

 

Okay, final report on this... replaced the connector with some shielded blade connectors from Napa... fan fired right up. :D