I removed my heater assembly to replace the heater core and put in new seals. Before resintalling it, I figured it a good idea to test everything so that I won’t have to pull it all out again for a long time hopefully. With the reassembled heater box sitting on the passenger side floor, I plugged everything back in and the blower motor won’t go. I’ve connected the blower directly to the battery terminals and it spins. I’ve checked every connection with a test light and am getting current at every connection - the fan switch at the controls, the two wires that plug into the blower motor, and the connectors at the resistor terminals that come out of the heater box - I’ve even made sure the fuse is okay - My test light is glowing at every connection, so I’m really running out of ideas. Does anyone know if there is a way to bypass the resistor connection just to see if that is where the problem lies. I don’t think that’s it, but I’m running out of any other good ideas. I’ve even gone so far as to hook up another fan switch from my parts car and the other heater assembly out of my parts car and it doesn’t blow either. There has to be something I’m overlooking here. It just doesn’t seem possible to be getting current at every point in the circuit, yet the blower still doesn’t spin. I’m open to suggestions! Thanks.
Not sure about bypassing the resistor.
But on our 93 Explorer and 03 Taurus, when the blower wouldn’t blow, it was the resistor.
Was an easy fix.
Sounds like a poor or no ground connection???
I’m with Harry on this. Sounds like a ground issue. I’d start there then look a the resistor.
Thanks for your help each of you on this very frustrating problem. The lack of ground did in fact turn out to be the problem, so I owe 1969eliminator and 1967 S Code a cold beverage the next time I get to White Rock, BC and Sumter, South Carolina! I ordered a new resistor from WCCC so I’ll just replace that while I’m at it - I broke the little plastic mounting stud thingies that hold the resistor in anyway, so I ordered a pair of those too.
Tracking down the problem really ended up being quite comical. Based on the grounding suggestions, I went to work this evening again with my test light and voltmeter. Everything still seemed to be checking out “normal” but as I was testing the fan switch I unplugged one and plugged in the other one I have. In the process of doing this - with the battery still hooked up and the key in the “on” position - I was fumbling with my voltmeter leads and accidentally touched the heater control assembly and switch to the metal part of the dash near where it should actually be mounted and suddenly there were some sparks and I hear the blower motor whir to life. So tonight I learned that for the fan switch to be grounded, it actually has to be securely mounted instead of just hanging from the dash by its connecting wires out of the dash! In my plan to test everything before mounting it in place properly, I had failed to realize that, at least in this case, mounting it is what makes the circuit complete. Whew! I sure do thank you guys for your help with this!