Broken Fan Switch Selector

[Ari]

Ah the joys of winter. No sooner does it set in in earnest up here in British Columbia than the most important part of a vehicle in the winter stop working. You may have guessed it... The Defrost fan.

A few days back the heater fan motor was making a squealing noise each time I turned the fan selector on. It didn't matter if it was on 1-4 or on high, it would intermittently squeal when turned on, and stop when turned off. I didn't think much of it, other than that it was annoying. Then while driving back from the coast a couple days ago, the switch jammed in the off position after being a bit stubborn to turn on. It was jammed pretty good, and against my better judgement I tried to force it. Sure enough, this led to something inside the dash snapping and now the switch moves freely back and forth while not doing anything whatsoever.

So, I know that I've probably broken a plastic internal part that turns a switch to engage the fan blower motor, but I am more curious about if perhaps the blower motor may have seized, causing the jam in the first place. If the motor is still good then I'd like to simply bypass the switch and put in a new aftermarket speed selector switch (not that I know how to do that, but I can learn with a bit of coaching...), but first I need to figure out why it seized up in the first place.

Any suggestions on where to start?

Thanks,
Ari

[timsrv]

It sounds to me like the fan motor is failing. It may have foreign material jamming it up, but the squealing noise you describe is usually caused by failed bushings. The result of either of these conditions is increased current draw to the fan motor. This most likely led to the switch overheating and failing. Usually the breaker will trip before a component will fail, but the Previa fan switches are a little weak and have been known to just fail under normal loads. Just for kicks you should check the breaker (link provided below) before getting too carried away on the switch.

Replacing the motor is done from under the hood. It's pretty straight forward and most people with average mechanical skills can do the job. The last time I did it I found the genuine Toyota fan motor was actually about 30% cheaper than any of the aftermarket stuff that was available. Of course that was about 5 years ago and things may have changed.

Replacing the switch is somewhat of a PITA but can be done by an average guy if you pay attention to detail and if you are patient. Here are a couple of links that should help:

http://www.toyotavantech.com/forum/showthread.php?288-Temperature-Control-Switch

http://www.toyotavantech.com/forum/showthread.php?145-How-to-disassemble-the-dash-on-a-Previa

These won't get you all the way there but will get you on the right path. Tim