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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: Joe dinubilo on September 18, 2014, 10:42:13 pm
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I'm working on my sons 1982 chevy 4x4 truck that he just purchased. The blower motor works fine until you switch it to heat then it blows the fuse. Any ideas on where to start troubleshooting this issue.
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I know that year of truck is different than what I am used to (73-80) models. I think I remember the switching mechanism might have some electronics to it.
On mine a cable moves the door, so something has to causing a short for you to blow the fuse when you switch to heater. I am sure others will chime in today.
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Did you figure this out?
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Still have not located problem with blowing fuse. Its a 1982 Chevy Truck if I set the selector switch to vent and turn on the blower switch everything works fine,as soon as I move the selector switch to heat,a/c or defrost it blows the fuse. I did replace the resistor and the selector switch and it still blows the fuse. I have hooked up the blower motor directly to the battery with a 20amp in line fuse, it ran 5 minutes and never blew the in line fuse. Anyone have any ideas where else to look or what else to check. Any input would be greatly appreciated.
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So clarify, is it the mode change that causes the circuit to open or the temperature selection from hot to cold? Which switch did you replace? The fan speed switch or the mode switch?
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its the mode switch, will not blow fuse in vent mode
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Sorry I did replace the mode switch
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Mine blows the fuse to the TBI computer when I turn the blower on high .
No clue how it's back feeding power or whatever
But I'm gonna have to run the Computer power streigt to the battery I guess
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Roundhouse - thread hijack unrelated problem you should start a thread on when you are ready to tackle problem.
Joe, is the truck AC equipped? What modes cause the fuse to blow?
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Yes the truck is a/c equip. here's a little more info I just figured out. If I set the mode switch to vent before I turn on the ignition everything works fine AND I can switch to heat but if I switch one more click to defrost or back the other way to the A/c settings it blows the fuse. When it does work all speeds on the blower motor work.
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Is your AC hooked up and functioning prior to this issue?
Unplug the connector at the AC compressor and see if it still happens.
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also if it has a throttle solenoid best check that too
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A/C is installed in the truck not sure if its functioning properly. Compressor is disconnected. My son acquired this truck a couple months ago. Never knew if A/c worked although all components are there and hookd up. Cannot test a/c because of fuse issue.
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Disconnected throttle solenoid and fuse is now holding. Thanks to all you guys for help on this issue very much appreciated.
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Glad you got it worked out Joe
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I fought this same problem forever. I figured out that there are separate power wires for the fan switch and the selector switch. I placed a Scotchlok connector on both power wires tying them together and that fixed the problem.