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Gary
Gary, Chevy Technician
Category: Chevy
Satisfied Customers: 16120
Experience:  15 years GM master tech
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My 1998 chevy tahoe fan motor goes on and off with out my

Customer Question

My 1998 chevy tahoe fan motor goes on and off with out my input. Some times it comes on half or full speed, on not at all( without my changing the speed switch) . Does this is indicate a bad switch or bad relay?
Submitted: 6 months ago.
Category: Chevy
Expert:  Gary replied 6 months ago.

the switch will be set to off and the blower will turn on my itself ?

Customer: replied 5 months ago.
No. When the switch is on, at any setting, it goes on and off. Often when the car hits a bump.
Expert:  Gary replied 5 months ago.

if you wiggle the electrical connection at the blower motor itself will the blower go on and off ?

Customer: replied 5 months ago.
Do I have to disassemble the dash to get to this connection?
Expert:  Gary replied 5 months ago.

no the blower motor connection can be seen under the passenger side of the dash or with popping out the glove box

Customer: replied 5 months ago.
I got the glove box off and wiggled the connections to the blower. It didnt come on. The selector is set to "high"
Expert:  Gary replied 5 months ago.

if its not running with it set to high speed can you see if you have 12 volts at the power wire at the blower with the truck on and blower set to high speed ?

Customer: replied 5 months ago.
There two wires plugged in, a black one and a purple one. I checked the black one and theres no voltage. I can't get the purple one to unplug. Or check it.
Expert:  Gary replied 5 months ago.

back probe the purple wire to test for volts

if the black is a good ground and the purple IS showing 12 volts the blower motor is bad

you can always get me back for FREE for any follow up any time with this question even after you rate me here at Justanswer

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Customer: replied 5 months ago.
The purp l e one shows 12 volts. Means the blower is bad?
Expert:  Gary replied 5 months ago.

that is correct

if the purple shows 12 volts and the black is a good ground the blower motor is bad

you can always get me back for FREE for any follow up any time with this question even after you rate me here at Justanswer

if you have any questions please ask as i do not get credit for my work until you rate me here at Justanswer

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