Fan switch or motor???
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From: Whispering Pines NC
Fan switch or motor???
What's the best way to diagnose fan switch or fan motor problems??? My fan motor works on high, but I can't get low or medium to work. Any suggestions?
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From: Standing still with all my might Texas
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St. Jude Donor '09-'11
Re: Fan switch or motor??? (MikeT)
That's probably just a fuse, the high blower is on a seprerate circuit than the lower settings.
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Joined: Aug 2001
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From: Standing still with all my might Texas
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St. Jude Donor '09-'11
Re: Fan switch or motor??? (MikeT)
Checked the fuse panel....all fuses good! Is there another fuse in the engine compartment or somewhere else???
Hmmmm
Check the blower resistor. If your car has AC it will be in the top of the evaporator housing on the left side of the firewall, I'm not really sure where they put it on non-AC cars but probably in the same area. It will have 4 wires going to it with two screws holding it in place. Mine had been severly Bubba'ed when I bought my car, you might pull it out and make sure that all of the coils are in good shape and not soldered together like mine were. :lol:
If there is nothing wrong there the switch will probably be the next thing to investigate.
Good luck.
Thread Starter
Instructor
Joined: Sep 2001
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From: Whispering Pines NC
Re: Fan switch or motor??? (Kevin_73)
Thanks Kevin, I know right where you are talking about! Will check when I get home tonight. I had my electrical tester out and checked the switch last night. Everytime I changed the settings (low-med-high) I got power through the wires coming out of the switch. Should I check up where the 4 wires go into the resistor for power??? I only see 2 wires (1 black, one purple) going into the fan housing, is that correct? By the way, I do have AC. Thanks for the help!!!!
Mike
Mike
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From: Standing still with all my might Texas
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St. Jude Donor '09-'11
Re: Fan switch or motor??? (MikeT)
If I remember correctly the 4 wires at the resitor consist of 1 that leads to either the blower relay or directly to the blower, and the other 3 go to the switch. Each leads to one setting on the switch, ie; only one wire should be hot at a time depending on which setting the switch is in.
The switch simply routes 12 volts out one of wires at a time, there are 3 different value resistor coils in that resistor. When you select the lowest setting on the switch the 12 volts should go to the resistor coil with the highest resitance, which lowers the voltage supplied to the blower. The next higher switch setting sends 12 volts to resistor coil that has slightly less resistence, and the 3 position sends 12 volts to the coil with the least resistence. They put the resistor inside the plenum for cooling because those coils heat up quite a bit from the resistence they provide. In most cases only one will fail at a time, so that may not be your problem.
I have a good wiring diagram for my 73, I'm not sure if it would apply to a 76 but if you need more help I can try to trace it for you.
The switch simply routes 12 volts out one of wires at a time, there are 3 different value resistor coils in that resistor. When you select the lowest setting on the switch the 12 volts should go to the resistor coil with the highest resitance, which lowers the voltage supplied to the blower. The next higher switch setting sends 12 volts to resistor coil that has slightly less resistence, and the 3 position sends 12 volts to the coil with the least resistence. They put the resistor inside the plenum for cooling because those coils heat up quite a bit from the resistence they provide. In most cases only one will fail at a time, so that may not be your problem.
I have a good wiring diagram for my 73, I'm not sure if it would apply to a 76 but if you need more help I can try to trace it for you.
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