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Is there a electric rear window FAQ or write up? I need some help.

T

trevor73402

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Hey guys,

My rear window on my '84 K5 does not work and I need to get it working so I can use my tailgate and cargo area. I don't even know where to start as far as checking things. I know that the cables and the motors are common problems with these electric rear windows. Is there a FAQ, write-up, or any other type of thread that shows how to diagnose issues with the rear window? How to check the cable? How to check the motor? Its in the up position and won't move. I've taken the panel off the back and can see inside, but don't know what to start looking for.
Any help would be appreciated.
Thanks,
 
trevor73402 said:
Hey guys,

My rear window on my '84 K5 does not work and I need to get it working so I can use my tailgate and cargo area. I don't even know where to start as far as checking things. I know that the cables and the motors are common problems with these electric rear windows. Is there a FAQ, write-up, or any other type of thread that shows how to diagnose issues with the rear window? How to check the cable? How to check the motor? Its in the up position and won't move. I've taken the panel off the back and can see inside, but don't know what to start looking for.
Any help would be appreciated.
Thanks,
Click to expand...

swap a manual tailgate on and call it done. Motorized windows on a well used utility vehicle are doomed to fail
 
You can remove the cable and spin it with a drill to open the window so you can work on it.
 
Where does the drill go? Do you mean remove the cable on the right side where it goes into the motor housing?
 
Remove the cable from the motor, put the cable in the drill chuck and spin the drill. Just make sure that you use a reversable drill and that you are going the right way. So take it slow at first till you figure that part out.

Is it just the key switch or the switch on the dash or both that won't let it work?
 
Neither one work, switch on the dash and the key in the back....both are dead. I'm gonna start with fuses, but I know it's not gonna be that simple, if it was the previous owner would have fixed it.
 
First things first. Make sure the wiring going to the back of the truck is still in one piece and that the connectors are plugged together. There are three connectors on the driver side that must be plugged together appropriately (only go one way anyway) for it to work. One plug is for the taillights, the other is for the window. These are the two square ones with four pins. I forget what the other is for.:doah:
 
Just skip to the tailgate area and work forward. Pull the plug off the motor with the gate up and have someone try the dash switch...use a test light and see if anything has power. My guess is no.

Open the tailgate once you have the window down (using the drill method). It's a ton easier to work on when it's down. There is an interlock switch that cuts power to the glass if the tailgate is not 100% latched, so roll the latches to the 100% closed postion with the tailgate down. Try the switch and see if you now have power. If you do, then the tailgate isn't latching 100%. If you don't then start tracing the wires forward until you find power.

That should get you started.

Rene
 
Ok,
I got the window down and the gate down.
I closed the switches and checked for power....dead.
I traced the wires back down the truck and thru the firewall and to the fuse block.
The fuse was blown so I swapped it out with a new one. I hit the switch on the dash and hear a pulse noise coming thru the radio speakers. I hit the switch the second time and heard the fuse pop.
So....I guess the previous owner has done some monkying with the wires. I've got a short somewhere. Any ideas? I'm gonna try it again tomorrow when I've got some light.
 
At least you know you have a short. Should be constant power to the motor, and the interlock, key switch and dash switch should provide grounds. IIRC the hot wire going back there is orange and pretty beefy (10-12 guage) Look for any bare spots I guess. Bad grommets, or areas where it could be rubbed through.

Rene
 
I wouldn't know about audio interference, but I did fix the electrical gremlins in the tailgate of my blazer, while I was digging for a used motor at the junkyard I ripped apart the rear tailgate of a suburban, some models also had a direct drive with a worm gear to spin the large ring gear for the window. The motors I came across are somewhat serviceable and have what looks to be a built in relay on the end where the commutator is for the armature, the short may be at that relay or the commutator, it may work if you blast all the dust and other garbage out with air. That's my guess, but by all means I am no electrician:dunno:
 
trevor73402 said:
Ok,
I got the window down and the gate down.
I closed the switches and checked for power....dead.
I traced the wires back down the truck and thru the firewall and to the fuse block.
The fuse was blown so I swapped it out with a new one. I hit the switch on the dash and hear a pulse noise coming thru the radio speakers. I hit the switch the second time and heard the fuse pop.
So....I guess the previous owner has done some monkying with the wires. I've got a short somewhere. Any ideas? I'm gonna try it again tomorrow when I've got some light.
Click to expand...

The tailgate motor itself might be dead and somehow causing the fuse to blow when you try to make the window go up or down and the power is sent to the motor but it doesn't move because it is frozen (kinda like a starter motor that is bad and will make the battery cable hot as hell if you keep trying to turn the engine over).
 
The wires for the rear gate exit the firewall near the engine on the LH side of the "dog house"

These have two plugs at the firewall exit area.

The other plugs are at the LH rear of the truck slightly above the bumper area.

Unplug the wires at the front first and then try the dash swith and see if the fuse pops, if not then try unpluging the rear plugs and see.

If the fuse stays ok then the short is in the gate, Motor or wiring.

You can hook a jumper cable to the one connector that has the spade that sticks out and ground the other jumper cable to the frame. Try the switch in the gate and see if the window works.

The motor could be shorted or the wires shorted.

These trucks usually have a bazillion miles by now and anything is possible

With the gate open you can remove the inner access panel and snoop out the inner workings.

There is an interlock switch that keeps the window from working unless the latch is locked (LH latch) could be the wire is shorted there.


Snowy
 
Inside the gate there are a couple of factory splice connections wrapped in tape. Pull the tape and check the condition of the splice. If it's all green and corroded that will cause problems.
 
Grounds grounds grounds

These older rigs can have serious issues with the grounds.

The tailgate is one area that is a real bugger.

Make sure that you have a good gound connection from the gate/window motor to the body.

If need be you can route a new ground from inside the gate, out under the truck and then fasten it to the body with a screw and star lockwasher.

Use a little dielectric grease on the connections too.

Snowy
 
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