Created on: 2018-05-03
How to diagnose a broken power window
Test Light
Flat Blade Screwdriver
Multimeter
Hi, I’m Mike from 1A Auto. We’ve been selling auto parts for over 30 years!
There's multiple issues that could be with this window not going up and down. One of them could be the window regulator motor and/or could be the wiring, or it could be the switch. We're going to start diagnosing by pulling the door panel off and checking for power and ground at the window motor.
Here's our window motor. We're going to test right here. First thing you need to do is disconnect the connector. Just a flat blade screwdriver, pushing the lock. Pull it out.
All right, so when we're going to test the circuit we want to make sure our test light actually works because then you could be testing a circuit with a bad test light. So when you start with your diagnosing, hook the one side to a ground, test the other side, the positive. As you can see, the test light is working.
To make testing this circuit easier what I'm going to do is I'm going to take a straight pick and put it in the backside of the test site so I have the ability to go in to both sides. We turn the ignition on. Next we're going to take our test light and just lightly touch the terminals. You do not want to force them in, just lightly touch them. I'm going to take our switch, activate the switch up and down. The test light is not coming on.
Okay, so the test light did not light up when we were checking for power and ground at the connector. Your next step would be to put your test light on a ground, on known good ground. What we can do is put it right here on this bolt. To make sure you have a good ground we're going to go over here. There's a power feed right here. You can see the test light lights up. That's that red and white wire right there in the back. All right.
We're going to go back to the connector, just lightly, again, don't want to break the terminals. Test it and then I'll activate the switch again, up and down. The test light does not light in the blue wire. We're going to move it to the brown wire and do the same. Still it is not lighting up.
We want to make sure our switch ... We know our switch has power here. Now we need to test that ground on the switch to make sure there's ground. We will go back, just take that in the power and test the ground. The switch has power in ground so we know that's good. But we know the switch is not sending power or ground to the window motor. We know that the problem is in the switch.
If when we were doing that test with the test light and when you probed both terminals and you were toggling the switch and it was lighting up, then you would know that it is the motor. But in our case it is the switch. One other test we can do is if you look at these two wires, the blue and the brown wire, these wires go from here and they go straight over to the switch. There is the possibility those wires could be open circuit. What I mean by open circuit would be the wire would have a break in it. If you think of it as like a garden hose going from here to there, there would be a split so the water couldn't go through. We can test them right here, just to confirm. There's still no power when toggling the switch, so it confirms this is the bad switch. If you diagnose your vehicle and determine that you need a window motor or a window switch, check 1aauto.com. We have a ton of window motors and switches and we can get your window working again.
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