My heat was only working on high. I replaced the blower motor resistor. This corrected the problem for about 2 months. It's now back to working only on high.

Anybody know what could be causing this? Or do I need to stock up on BMR?

Any help would be appreciated.

Thanks

The Blower Motor Resistor is, well, a resistor. It resists electricity and gets hot, resists more to produce a slow fan speed and less to produce a fast fan speed. The more electricity it resists, the hotter it gets. I've seen it written that when a Blower Motor gets old, it often draws more power than normal causing the Blower Motor Resistor to get more hot than normal, leading to premature resistor failure.

Learning this, I decided to replace my Blower Motor and Resistor at the same time. I also replaced the Blower Motor Relay which I also learned can become pitted and lose effectiveness closing the circuit through the contacts to provide power to the Blower Motor. I replaced all three items for less than $80 and haven't had any heater problems at all... in over a year since I made the repairs.

More:

http://www.automotiveforums.com/vbulletin/showthread.php?t=340871

So far so good.

It's been 5 months since I have replaced both the blower motor resistor($20.00 Dealer) and the blower motor realy($7.00 AutoBarn).

I hope I'm not jinxing it.

Thanks for the help,

Anthony