i have a 94 pickup and the heater works but the blower only runs on the low speed i have checked the fan and it is good i have replaced the resistor and no luck is there a chance that the switch itself is bad any input will be greatly appreciated thanks

 

I just did a search because I've had the same issue, mine only works on speed 1 2 and 4. It seems from what I read that the switch gets hot on speeds 3 and 4 and burns out. One guys switch actually melted and stopped working all together. Another member said that he noticed a spike in the voltage on the switch when starting his truck. So I would suggest replacing the switch or taking a look at it to see if you can tell if it is burned up or not. I'm gonna try this same thing. I didnt think about getting the link to the post I read, but i'll search again and post the link when I find it. I also have to search how to replace the switch because I've never looked at any of this stuff before.

 

OK, here is the link to the post I read.
https://www.yotatech.com/forums/f131...t-down-163236/

Hope this helps, I'm gonna start searching how to go about swapping out the switch now.

 

Could be the switch, see if you are getting power to the motor or resistor in the non-working speeds. If not, check the switch, common problem is burnt contacts.

 

I guarantee its the heater resistor. It did the same thing as my truck...but only worked on high. Its right by the passenger side (where your feet are). It has two screws and unscrew it and unplug it. Mine were fried and missing. Except one (the high speed!)

Anyway, check it out...it bet its your problem. It costed me $35.

 

With a bad resistor, you start losing the slower speeds and only have high speed left when the entire resistor is gone. The various resistances are added in series with the blower motor to make it run slower and only in high speed is power sent directly to the motor:
- http://www.4crawler.com/4x4/CheapTri...BlowerResistor

 

Yeah, that is why I only had the high speed. Because there is no resistance needed

So, there is a chance it isn't because he mentioned it only working on the low speed.

Thanks for correcting me