85 GMC power window help needed asap

[68c10owner]

I need help from you guys. I just went and looked at a 85 GMC swb and my only issue with it is the power windows. The driver side is slow but works. Pass side Wil not work from the pass side switch and the brier side switch has to be flipped off and on a bunch of times to get it to work. If you hold the switch down it just stops. Since the a/c doesn't work and we are having 100+degree days I need the windows to at least roll down. I can get this truck for a smoking deal but since I have my kids in the truck I need some sort of air moving through the cab. I guess my question is, is this going be a expensive and time consuming project to get the windows working like they should? Is there a upgrade that would make them better than stock?

[turbosix]

Originally Posted by 68c10owner

I need help from you guys. I just went and looked at a 85 GMC swb and my only issue with it is the power windows. The driver side is slow but works. Pass side Wil not work from the pass side switch and the brier side switch has to be flipped off and on a bunch of times to get it to work. If you hold the switch down it just stops. Since the a/c doesn't work and we are having 100+degree days I need the windows to at least roll down. I can get this truck for a smoking deal but since I have my kids in the truck I need some sort of air moving through the cab. I guess my question is, is this going be a expensive and time consuming project to get the windows working like they should? Is there a upgrade that would make them better than stock?

In most cases the windows are a simple fix. The motors and switches are the most common problems and both are not hard to replace. I personally would change our both motors and switches and be done with it. Depending on quality, that should last for years. I also grease things while I'm in there.

[gmachinz]

With 30 year old switches and wiring, if you plan to keep the truck for awhile, wanting the windows to work better than stock involves adding a relay trigger harness of which there are a few options-newer vehicles have better operating power windows mainly because they use a ground trigger system instead of routing power through a switch. New vehicles have now made a switch to solid state relays built into the BCM (body control module) but you can also too.

[68c10owner]

Originally Posted by turbosix

In most cases the windows are a simple fix. The motors and switches are the most common problems and both are not hard to replace. I personally would change our both motors and switches and be done with it. Depending on quality, that should last for years. I also grease things while I'm in there.

I ended up buying the truck afterall. Too good of a deal to pass up. I am going to replace the motors and switches on both sides. Maybe the regulators too.

Originally Posted by gmachinz

With 30 year old switches and wiring, if you plan to keep the truck for awhile, wanting the windows to work better than stock involves adding a relay trigger harness of which there are a few options-newer vehicles have better operating power windows mainly because they use a ground trigger system instead of routing power through a switch. New vehicles have now made a switch to solid state relays built into the BCM (body control module) but you can also too.

I'm not sure how long I'll keep the truck but have no current plans to sell it. Lots of upgrades I want to do including one of your wire harnesses. Just need to figure out which set up I need.

[tucsonjwt]

You need to check the connectors/harnesses on the switch and motor first.

Remove door panel.

Reach down inside the door and remove the connector to the motor (remember which way it goes in because you won't be able to see it when you reinstall it.)
Get a simple 12 volt continuity tester and stick both probes into the contacts in the connector. (You will need a short piece of copper house wire (like 12-2 wire) attached to the alligator clip to make the second probe.) Operate the switch with the power on and see if the tester lights up. If it lights up, then the switch and harness are good up to the motor, and you need to replace the motor.

If the light does not go on, then wiggle the connector behind the switch to see if you can get the light to go on. If you can get the light to go on, then the connector and/or harness are bad - replace them.

If you have no power going to the switch, then your problem is further upstream (break in wire in the door or further along to the fuse block.)

I thought that you needed the relay mod you can read about on this forum to get good windows, but if you get an AC Delco motor (without mounting brackets pre-installed) the windows will work fine (not as fast as a new truck, but fast enough for me, and definitely not slow.) Check www.oewarehouse.com or www. oehq.com for motors if you need them (but you likely have other problems, I guess.)

[68c10owner]

Originally Posted by tucsonjwt

You need to check the connectors/harnesses on the switch and motor first.

Remove door panel.

Reach down inside the door and remove the connector to the motor (remember which way it goes in because you won't be able to see it when you reinstall it.)
Get a simple 12 volt continuity tester and stick both probes into the contacts in the connector. (You will need a short piece of copper house wire (like 12-2 wire) attached to the alligator clip to make the second probe.) Operate the switch with the power on and see if the tester lights up. If it lights up, then the switch and harness are good up to the motor, and you need to replace the motor.

If the light does not go on, then wiggle the connector behind the switch to see if you can get the light to go on. If you can get the light to go on, then the connector and/or harness are bad - replace them.

If you have no power going to the switch, then your problem is further upstream (break in wire in the door or further along to the fuse block.)

I thought that you needed the relay mod you can read about on this forum to get good windows, but if you get an AC Delco motor (without mounting brackets pre-installed) the windows will work fine (not as fast as a new truck, but fast enough for me, and definitely not slow.) Check www.oewarehouse.com or www. oehq.com for motors if you need them (but you likely have other problems, I guess.)

I appreciate the input. I do have a test light and a continuity checker so thats not a problem. I have a pretty strong mechanical background but never had to mess with power windows.

Being that the truck is 30yrs old I am planning to go ahead and replace both motors with AC Delco units, new switches and a new wire harness kit for both doors with the relays from gmachinz. Looking forward to playing with this truck and doing some modern upgrades. This is going to be a daily driver for now so first thing is getting the windows working perfect so I can at least get some air moving through the cab and then tackle the a/c system.

[tucsonjwt]

Check the power at the motor first, before you throw more parts at it. You may find that all you need is a new harness. I have only had one bad window switch and one bad motor in 20 years of owning old squares, but I did replace all of the parts due to my ignorance.

If these windows worked well from the factory, why would you need a relay upgrade? I am not saying it won't help, but it should not be necessary if all else is good.

[68c10owner]

It's not necessary to do the relays but from what I've been reading it helps the motors live longer and work better. Sounds like a win/win situation to me. And you could be right, might be something simple but being that the truck is 30yrs old I'd feel better about replacing the parts.

BTW, I started this post before I decided to buy the truck. I did some looking around and found the thread about the relays and I like the outcome. Just didn't want people to think k I asked for advice and now I'm not taking it. I do appreciate it and if I hadn't found out about the relay set up I'd be following your advice. I do t have a lot of time to mess with this either so replacing everything at once makes it a one and done issue and hopefully I won't have to get back in there for quite a while.

[crazeetxn]

Just replaced the switch, connector switch, and motor on mine. The drivers sides goes up and down no problem. The passenger would hesitate up. Come to find out, it's the driver's switch causing problems. If I hold it just right, it'll go out without hesitation.

Here's a link for getting the regulator out. All I can tell you is to make sure the window is UP before you go to pulling. For some reason, I left that part out of the puzzle and had to hook the motor that was dying back up to get it up. Couldn't get the regulator out with it in the down position. Also, I didn't have my vice set up so I ran a screw threw the half moon looking piece with the teeth on it to keep it from moving.

http://www.73-87.com/7387garage/interior/winmotor.htm

[68c10owner]

Originally Posted by crazeetxn

Just replaced the switch, connector switch, and motor on mine. The drivers sides goes up and down no problem. The passenger would hesitate up. Come to find out, it's the driver's switch causing problems. If I hold it just right, it'll go out without hesitation.

Here's a link for getting the regulator out. All I can tell you is to make sure the window is UP before you go to pulling. For some reason, I left that part out of the puzzle and had to hook the motor that was dying back up to get it up. Couldn't get the regulator out with it in the down position. Also, I didn't have my vice set up so I ran a screw threw the half moon looking piece with the teeth on it to keep it from moving.

http://www.73-87.com/7387garage/interior/winmotor.htm

Thanks for the link. Ordered 2 new AC Delco motors and 2 AC Delco switches from Rock Auto this morning. Planned on getting the harness from gmachinz too but funds ran short this month. If the motors and switches dont fix it then I`ll just have to come up with the money for the harness kit.