1986 GMC C3500 Rear Power Window Regulator

[cjlloyd81]

I'm at a brick wall here. I've located/ordered/have motors for all four windows, and window regulators for the front doors. Orielly's, AutoZone, NAPA, Classic Indusries, JC Whitney, LMC Truck... all are making me think I"m crazy because no one lists or can find regulators for the rear windows. The ones for the front in every system/catalog specifically state Front Driver, or Front Passenger.

Short of pulling them out (cause thats alot of fun) and comparing to the front's... Can anyone tell me if they are the same front/rear?

1986 GMC C3500 4 door long bed dually. wings on the front window, and inop sectional glass on the rear.

[mrolds88]

Use Suburban as application. same thing. BTW. Interesting visor, any info on it??

[cjlloyd81]

Oreilly's parts listing for a '86 GMC Suburban. Still only shows front windows...

[RandyP]

Maybe having the OE part #'s will help. Here is the listing for the back door window regulators for an 86 C3500 crew cab. Heck it shows the left side is still available from GM for $135.70 retail.

[mrolds88]

Does the truck have power windows now and you want to replace or are you upgrading? If you are replacing, what is wrong with whats in there now?

[cjlloyd81]

Power windows are factory. I'll have them cross those part numbers but I got a feeling they're going to come back as the front regulators.

[RandyP]

Fronts and rears are totally different parts.

[motornut]

nice truck
you can use manual ones till you find them,crank comes threw the switch hole

[rs72z]

Unless the roller has gummed up and bent the regulator there's not a lot to go wrong with them. Most just need a good cleaning and greasing.

[cjlloyd81]

Originally Posted by mrolds88

Use Suburban as application. same thing. BTW. Interesting visor, any info on it??

No, no idea on the visor, the rear cab fin, or the bed cover. Just that the bed cover is custom aftermarket, and from what I was told by the original owner the visor/fin came on it. It was a custom order by a Chevrolet dealership owner originally.

Unless the roller has gummed up and bent the regulator there's not a lot to go wrong with them. Most just need a good cleaning and greasing.

When I bought it none of the windows worked, or even tried to go down. So I got a new/reman motor and took the drivers front door apart. Changed the motor, put WD40 on every moving part of the regulator. I also manually moved the regulator, and used the motor prior to installing it back in the door. (could they make that any more fun? really...?) The window worked well for a month, tho it came to a stop at the 1/2 way mark till you touched it then it'd go the rest of the way. And now nothing, not even trying to move. I'm got a new regulator that'll be in tomorrow, and I'm going to warranty the motor as well.

I did spray wd40 down the side tracks of all 4 windows and since then the RR window will open and close tho its slow.

Thanks for all the attention and ideas guys I really appreciate it.

-Chris

[joe231]

Wd40 is not a good lubricant. I would either use grease or some spray lube like silicone or white lithium.
PB blaster makes a garage door spray lube that works great.
http://www.blastergroup.com.au/garag...lubricant.html

[mrolds88]

I'm with Joe. Also you might want to look into the relay mod that is on here. Also sounds like the problem is electrical. Check over your switches and wiring. Switches are easy to disassemble and clean.

[joe231]

I agree, in my experience the old corroded switches are usually the culprit. Disassemble, clean the contacts and apply a good dielectric lube on them. Don't forget to clean the connectors and pins on the back of the switch. A little dielectric there helps too. You might even need to bend the contacts in the connectors to make better connections also. Corrosion at any of the connections will drop the voltage that actually makes it to the motors. You can even replace brushes in the motors and clean the commutator while apart. It's not extremely difficult, just takes some patience. All these things need maintenance, but most never receive any attention.

[cjlloyd81]

I never thought of that... When I have my drivers door apart I'll play with the multimeter and check for resistance.

Thanks guys.

[cjlloyd81]

Well I totally didn't think of the switch as a possibility. So thank you all for suggesting that. I took the Drivers door panel off and jumped the connections on the plug itself and every window worked, passenger front was slow but they all worked. So I cleaned up the terminals on the switch plate, tightened the connections in the plug and still had the same problem.

I had an already scheduled meeting with someone to buy a Qjet and SBC manifold (just wanted the carb but for $40 couldn't pass up the included intake) and it so happened he was parting out an 80's suburban while I was there so I picked up every switch the suburban had (the 4 switch drivers door window switch, three single window switches, and two lock switches) for $20 extra.

Brought the new switches home and plugged the 4 switch window one in and jackpot. If anyone that helped with this is ever in southern Oregon let me know, I owe ya'll a beer. You saved me a lot of money from replacing all the motors and regulators. So thank you again.

-Chris

[joe231]

Awesome!!!
Glad it worked out for you!

Btw, what kind of bed cover do you have on your truck?
Any pictures?

[mrolds88]

Good deal, Chris!! Now that you have this figured out, look into the relay mod. Also the window that is slow, check the in door connections and do a re lube. Might do more wonders.

[cjlloyd81]

What relay mod?

[mrolds88]

Here's 2 threads that should help you out.

http://67-72chevytrucks.com/vboard/s...t=window+relay

http://67-72chevytrucks.com/vboard/s...t=window+relay

[cjlloyd81]

Originally Posted by joe231

Awesome!!!
Glad it worked out for you!

Btw, what kind of bed cover do you have on your truck?
Any pictures?

I don't have any right now, but tomorrow when I go back out to putz around I'll take some. It's like a pre-Avalance type design. Sectional, that removes to allow access to the in bed kingpin.