Blower running on high

[Hardrock52]

I have a 2000 Explorer Eddie Bauer. The blower motor only works on high. In auto mode the blower is on high all the time. Even when you hit the off button, the blower keeps on running. Any ideas? Is it the resistor and where is it located?
Thanks

 

[koda2000]

seems like we get this question every week or so. you have what's called a blower control module. it is located at about the five o'clock position relative to the blower motor, under the hood on the passenger side of the engine compartment. sometimes this electronic module becomes dirty and you can remove it, take it apart, clean it up and have it work again, sometimes you need to replace it.

 

[Hardrock52]

Thanks, when I get a chance I will remove the module and take a look at it.

 

[J_C]

On models with the auto climate control module, the portion in question consists of a darlington transistor rather than a few resistor(s). More info about that is in my post here:
http://www.explorerforum.com/forums/showpost.php?p=3278612&postcount=5

A web search will find various methods of testing a darlington transistor with a multimeter including this one: http://www.ehow.com/how_8046802_test-darlington-transistors.html

Briefly one possible failure mode of a transistor is that it can become leaky, meaning it passes current even when there is not a corresponding drive current applied to the base pin by the driving, control circuit. If the transistor has failed it is much cheaper to just replace the transistor itself instead of the whole module. However it may be possible that the head unit rather than the resistor went bad so I do recommend checking it.

 

[koda2000]

before you get into replacing transistors just try cleaning the module. you'll be surprised how filthy these get due to being in the outside air stream. there's a small black plastic cover, under it is a circuit board. clean that too. use contact cleaner. also check and clean the wiring connector. there was a good post about this about a month ago. i'll see if i can find it and post a link.

sorry, i couldn't find it.

 

[Hardrock52]

I removed the module and cleaned it but no change.

 

[koda2000]

I removed the module and cleaned it but no change.

well. it was worth a try. you can try replacing that resistor, or replace the module. they're a bit pricey, so you may want to try a salvage yard, or just get a new one. prices vary quite a bit (check RockAuto and Amazon). someone here had bad luck with several he'd gotten from O'Reilly's so you might want to stay away from them.