Power window woes.

Thanks in advance for any help. This forum has saved me thousands in repair bills over time.

I have a 99 Silverado. In March 08 the driver side power window regulator went bad. (Broken cables) I replaced it with an aftermarket assembly. Worked fine other than being slower than OEM.

Recently when operating window I began hearing occasional loud "thumps" as window went down. Now when window bottoms out it continues "banging" and the motor won't stop unless I momentarily hit the "up" switch.

It's like the switch won't turn off the motor. I tried a new switch with no change. Replaced all the relays to be sure that isn't it. Today I'm going to run extension wires from dr side to passenger window and see if it works right. At least I'll know all the switches/relays are good..

I'm thinking theres a broken tooth in motor/gear mechanism. Shouldn't happen with a 6 month old part but I'm out of options. Is there a way to check the teeth. At a quick glance doesn't look like the motor/gear unit can be disassembled. The one thing that leads me away from the tooth idea is when I lower the window. It's Ok till it hits bottom. The cables tense up compressing the dampner spring. When the spring bottoms out the bang occurs and the cables go slack for a moment until the dampner bottoms out again.

Any input will be appreciated-Capt. Delta

I'm guessin' that there's an electrical contact - one for up, and one for down, 'complete cycle'.

See if you can find the FACTORY schematic for the window. Betcha you can find exactly what the problem is before turnin' a screw...

I have done many of these window regulators...quite common....the place I purchase from is 1A auto located in massachusetts....these are oem/or high quality units with lifetime warrantee...the last shipment I recieved was for the 2002 silverado both driver/passenger units deliverd to my business for 150.oo us...


your problem is only going to be solved by the replacement....and these cheapy made units have a high failure rate...


this company has a cheap low quaity unit...I would not get that type....get the other ones...you'll see....the difference..


I also recommend silicone spray on the rubber window slides....then that window will move much faster ..this is good to do every 6 months...

cbec and JCat thanks for the reply. I checked the switches by running extension wire to the passenger side window and it worked fine. Replaced the regulator with a new one from NAPA and it fixed the problem. I pulled apart the old motor and gears to see what had broken. The worm drive and teeth were all good. But the housing was filld with shredded rubber or composite. Looks like there may have been some kind of dampner for the gears that failed. I did spray the new tracks with silicone sparay and it seems to be a lot smoother than the old one. Thaks for the help.

cbec and JCat thanks for the reply. I checked the switches by running extension wire to the passenger side window and it worked fine. Replaced the regulator with a new one from NAPA and it fixed the problem. I pulled apart the old motor and gears to see what had broken. The worm drive and teeth were all good. But the housing was filld with shredded rubber or composite. Looks like there may have been some kind of dampner for the gears that failed. I did spray the new tracks with silicone sparay and it seems to be a lot smoother than the old one. Thaks for the help.


no problem capt...I have another suggestion though.....when you hit the down switch and it goes express all the way down,,, stop window from bottoming out ....hit the switch up to stop this...this will reduce the stress on assembly..

how much was NAPA ??? did you check out 1A auto????

no problem capt...I have another suggestion though.....when you hit the down switch and it goes express all the way down,,, stop window from bottoming out ....hit the switch up to stop this...this will reduce the stress on assembly..

how much was NAPA ??? did you check out 1A auto????

The NAPA OEM regulator was $81+tax. A lot cheaper than the last one I go from another store. ($136) and seems to be better built. I didn't check 1A because the Napa store was down the street and they've always done right by me.

The NAPA OEM regulator was $81+tax. A lot cheaper than the last one I go from another store. ($136) and seems to be better built. I didn't check 1A because the Napa store was down the street and they've always done right by me.

thanks ...that price you paid is close to 1A...NAPA has a good high quality part inventory.....

If you lube the cables with lithium grease and spray the rubber guides with silicone every year you should have no problems..