2004 Pontiac Grand Prix

Alright, here’s a doozy/head spinner/hangover in the making: I just moved to Bloomington, Indiana and the very first weekend here I broke the left rear power window regular and possibly motor in her 2004 Grand Prix. I figured, not a problem. I ordered a brand new out of box power window regulator for the left rear, installed it, but when it came to connecting it to the cabling I noticed its dead in the water. The front driver’s switch won’t work, nor will the left rear switch work. I tried every other switch in the car. Everything else is working fine except for the button on the driver’s switch that controls the left rear and the left rear switch itself.

That said, I’m in a bit of a pickle. I have this brand new part that isn’t working. Is it possible I have a wiring failure? Is it a fuse issue? Or, worst case, do I have two bad switches (this seems the least likely).

Any advice or fun poking at my misfortune would be greatly appreciated.

P.S. Things I’ve already tried

-Going in to a Napa to see if they’d help diagnose. The guy just told me it sounds like a fuse issue. Is it possible that a fuse would go bad and only cause an issue for one window?
-Checking all cabling to make sure it’s connected correctly.

Thanks community

Get a volt-ohm meter and check the switch and wiring for continuity. Let us know what you find.

Look at would be the wires going from the door to the body, that is one of the more common points of failure.

I don’t own a meter here, as I’ve just moved. Do you know if Autozone would loan me one?

They are cheap at Harbor Frieght.

They are cheap just about anyplace. I picked up a basic one for $10 at a local hardware store and a slightly better Craftsman one for $20. A test light would also work (for voltage but not continuity) and should be cheap at any auto parts store. Your first order of business is to check for the 12V at the connector.

More than likey it’s either the driver door or left rear door switch.

It’s not a broken wire in the door. If it were none of the windows would work.

Since the rear door is apart, remove and unplug the switch. Looking at the switch, figure out where to insert a jumper wire in the connector to make the window either go up or down. If the window operates it’s the left rear door switch. If the window doesn’t operate it’s the drivers door switch.


Hey folks. Thanks for the help. I used a multimeter and found out there was no issue. When I originally had everything connected, I simply didn’t have it connected well. Everything is back in place now, and I am the proud owner of an analog multimeter. I am sure I’ll need it eventually.

Please keep it mind that if you are ever installing a window regulator on a Grand Prix, make sure everything on the door is connected (wires to regulator, wires to switch, or it won’t function.

I feel pretty stupid for starting a thread about this, since the fix was so simple, but thanks for the help anyways.

Oh, good Lord, don’t feel stupid. You just diagnosed and repaired a failed power window… twice!!!

And thanks a million for the closure. Even though I didn’t help on this one, it’s always great to hear a story with a happy ending. And we rarely even hear the ending.

Happy motoring.

Analog multimeter?

That’ll work fine for things like power window circuits. But don’t use it on computer controlled engine components.

Most of these components only operate on a 5VDC reference signal sent by the computer. If you use the analog multimeter to test these components for resistance, the meter sends a 9VDC reference signal. That 9 volts will fry the component that was only supposed see 5 volts.

You should have bought a cheap digital multimeter with a 10 megaohm impedence. These type of meters allow you to test any component on the vehicle.


Thanks for the input, Tester. For the purposes of my inquiry, it worked fine and was able to show me there wasn’t an issue. I’ll keep the analog meter for household purposes only. Next time I need anything for a computer component I’ll get a digital one.

That said, if anyone needs any help installing a power window regulator for a Grand Prix, I am officially your guy.

Note that I had a GM vehicle of that general vintage. And I have never had so many dumb little random problems. And a ton of the dumb little random problems were just because the electrical connectors throughout the car - well, basically stink. I did plenty of “disconnect, clean connection, fuss with connector, reconnect, and…fixed.” In one respect it is a relief, of course. So when I fixed my own sluggish and occasionally dead power windows with plug cleaning, I was obviously thrilled. But make that a note to self. Any problem on this car that has electricity involved - do the simplest possible stuff first.

Speaking of GM vehicles

When I was at the Benz dealer, I saw my fair share of electrical problems. The cars were NOT known for being reliable

Now that I’m a fleet mechanic, many of the vehicles are GM. I’ve never seen so many melted and overheated connectors, pigtails and fuse boxes in my life!

Pathetic . . .