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New User

Apr 28, 2005, 9:04 PM

Post #1 of 3 (1647 views)
89 blazer Sign In

I picked up an 89 S-10 and had to replace the drivers side power window motor that was missingf. I have power thru the harness to the switch but the window does not work.I'm guessing the switch? or maybe is there a relay somewhere? How do I go about testing the switch and or relay once i find it?
Any input would be most appreciated.
Thank You

Veteran / Moderator
DanD profile image

Apr 29, 2005, 5:00 AM

Post #2 of 3 (1640 views)
Re: 89 blazer Sign In

At the drivers switch make sure you have power at the pink wire, a test light connected to a good ground is the easiest way of testing.
If you do then unplug the motor and connect one end of your test light to the brown wire and the other end to the dark blue.
Now toggle the switch in both the up and down positions the test light should light in both directions.
The drivers switch has two functions it supplies power the motor as well as the ground. In the up position the blue is power and the brown is ground, in the down position the brown is power and the blue is ground. In the rest position (off) they are both connected to ground.

Canadian "EH"

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Apr 29, 2005, 9:12 AM

Post #3 of 3 (1629 views)
Re: 89 blazer Sign In

Dan is amazing! A quick trick I try to determine motor or power/ground problems is with engine off but in run position try a window that works with the interior lights on. Ask a window that is already up or down to go up or down again for a second and watch the dome light dim a bit. It's getting proper power/ground. Then try that on the one that doesn't work.

If you don't see that it's usually a power/ground problem and then get to work. If it dims for window that doesn't work it's usually a problem with the motor.

I find some bad switches and the tricky one is the wire breaks where it has to bend in the rubber snorkle in the door jam. If you get to the point where you suspect that pull gently on the wires from the inside and the broken one comes out!

Looks like you may spend some time with a test light. The switchs alternate power and ground for up and down - both must work for the motor to work as Dan said the motor needs to be supplied both.

Good luck with the fix,

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