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Discussion Starter · #1 ·
hey guys. usually I can ready older threads and fix my issues but I need help with this one. My fan is not working. It used to work and went out a couple months ago. I pulled the connector to the blower motor and tested it for power. None. I checked the #9 fuse and it was good. I swapped it with another 30 amp fuse to double check. Still no power at the connector to the blower motor. Then i ran power direct to the connector end that goes to the blower and grounded it - fan spun. I changed the control switch in the cab to low from high but it didn't change the speed. i pulled out the fan control switch and checked for power there - nothing. so I need power. where/what should I be checking?
 

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If I'm not mistaken, there is a fuse under the dash as well.
 

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IIRC there's also a rheostat under the hood on the heater housing that can go bad. I think all the juice has to go through it before it goes to the fan.
 

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Pull out the glove box liner, there is a ceramic block on the side with coils on it, you'll find broken coil wires. IIRC that's where it was on my 90.

Any parts store has them.
 

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What year truck? (No, "the one in my sig" is not an answer....)

The above references are to the resistor block (not a rheostat really, just a set of resistors). IIRC, that resistor block is bypassed when you switch to HIGH. So reconnect everything and try the fan on HIGH. If it works, that resistor block is the prime suspect. If not, the problem is likely upstream electrically - power to that fuse, or the fuse connection. Possibly even ignition switch, depending on whether anything else is inop. Did you check for power at the fuse socket with the key in RUN?
 

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Discussion Starter · #6 ·
madpogue - i woke up thinking the same thing this morning. I checked it and there was power at the fuse connection, but the fuse didn't seem to be connecting well. I loosened the fuse box and shoved the wire going to that fuse in further, slide the fuse back in and bam, i got power. fan fired up and the speed controls work - lo to high. However, air flow only flows out the defrost vents. is this the control unit or something else?
 

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Discussion Starter · #7 ·
did some more reading. sound like it is vacuum related. i found a vacuum valve/selector under the dash left side of glove box. i manually pushed it in and the air then started flowing through the upper vents. so I guess I do not have vacuum to this selector/valve? i checked the line going into the heater box/behind AC unit in the engine compartment and it has vacuum. does it go from there to the climate control?
 

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This shows the problem with the blower fuse:



This shows the blower resistor:



These show the vacuum lines:

.

This shows the coffee can:

 
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