A/c blower motor on 94 S-10 Blazer acting up


#1

Seems to only work on high and have to have car running, control switch set on high, and go under hood and either tap the relay or unplug and replug power lead (purple wire to motor. Motor immediately comes on full blast. If car is turned off, or control switch is turned to lower setting, blower stops. I can still feel cold air coming from vents, but am not sure whether the low setting is working or if it’s just coming out without the blower.



I replaced the relay, since tapping the old one made the blower come on in the manner described above. But it’s still behaving the exact same way with the same response to tapping or interrupting the power source briefly.



Could it be a resistor? and if so, how do I find it? Is it in the form of a wire? I have the shop manual, but could not find my car’s symptoms in the trouble tree and could not tell from the diagram where that resistor might be.



Thanks!


#2

Yes it is a resistor, or more correct the resistor block which is a number of resistors. On most cars it is mounted so the air blowing from the blower will go over it cooling the resistors. You can get a replacement from your dealer and looking under the dash where the blower heater and A/C are located you should be able to find the original part.

If you are young and flexible it might even be easy to replace. :-) 

Good Luck


#3

Thank you very much. I finally found the block which, in this case, is located in the engine compartment, in the evaporator case. MUCH easier to get to than under the dash. I ran the trouble tree test and the result says to replace the resistor block.

I’ll let you know if that fixes it, but I’m pretty sure it will with your input and the info in the shop manual.

Thanks!