Hey Everyone,
Ever since I got my Bronco four years ago, the rear window has been sluggish, especially in cold weather. I've posted this question before on numerous occasions, but never seem to get any help on the matter.

I've completely greased and lubricated every moving part of the rear window mechanisms. I've even had it professionally done. I've also replaced the rear window motor.

I've been told on numerous occasions that it could be a ground problem (which makes sense), but whenever I ask where it is, either the thread loses interest, or someone tells me that the ground is located behind the driver's side taillight. I'm not sure if this is the case on later years, but on an '81, it is not behind the taillight. The only ground there is for the taillight itself. The wires from the motor just go into a large bundle, become wrapped up with 20 other wires into the wiring harness, travel the length of the frame, and disappear into obscurity.

If anyone knows exactly where the ground for the tailgate is and where it is bolted, I would be greatly appreciative. It'll be getting cold soon and I get tired of having to get out and pull and push the rear window up and down by hand while activating the switch.

Thanks for any help!

 

acording to my 82 diagram from ford it is behind the radio. contact me if u want to discus this problem further i have the same issue

 

Please keep it in the forum so others can benefit from the discussion!

 

While I can be of no greater assistance with the location of the ground in this model year, I can make a suggestion to determine if this truly IS the problem short of tearing up the entire wiring harness all the way back to the front of the truck.

Find the ground wire in the tailgate for the window motor and run a temporary ground to a clean spot on the frame (clean a location for it if you need to) and see if the window runs any better with a strong ground in place. If it does, make your temporary ground run your permanent ground run and be done with it. It really doesn't matter where the motor is grounded as long as the connection is strong.

If this doesn't rectify the problem, then you are into things like dirty or sticky mechanisms or a dying motor.

 

I had this same problem on 1 of my 78/79 style Bronco's,..after doing all the same things already discussed,I had a friend that was a electrician and he asked if it was getting a full 12volts,naturally I said yes it is working ,just slow, so he decided he would show me up ,so he got out his meter and what do you know it was only getting 10.2,...so he started tracing back the wire and found in 2 spots where the insulation had cracked ,under the Bronco and under the hood,....both spots were still connected but green ,and very thick,.....fixed both spots,...what you know ,the window works and worked faster than I have ever seen one work before.......just my 2 cents worth

 

Thanks for all the advice. That's what I'm figuring it is. Somewhere along the wiring is an issue. Also, Greystreak, I might as well just not even do a temporary ground and just make a new permanent one.

I'll get out a voltmeter and check the voltage. I bet it's not getting all the juice it needs. As said, it's a newer motor, and has been lubricated.

Behind the radio makes sense on the current ground, since that's where the front cab switch is.

 

The wiring diagram shows that there can be no ground at the motor.the switch switche curent flow from one side to the other to change direction up/down so i am thinking that the voltage being low is probably the problem. I think i would just run new wires up to the switch if that is the case....my 2 cents

 

Very good information to know. I guess I'll have to pull the wiring out and recheck/replace it all. Oh well, new weekend job.

 

If all else fails, my two cents would be play around with adjusting placement the tailgate and the way the top sits. You may not have more than a fraction of an inch of play, but if the window is rubbing against the inside of the channel in the top, even a motor running tip top will be slowed down by the friction.

 

The ground is carried to BOTH switches through the center poles and ONLY attaches to the switches and the grounding point directly. The switches also carry the power feed to TWO sets of contacts. When the switch is depressed one direction, the points close between one set of contacts and the power feed and another set and the center grounding contacts. When the switch is depressed the OTHER way the set of contacts that carried the power feed before, now carry the ground and a third set of contacts close to complete the power feed. The switches are dual throw so there are always two sets of points closing and one opening when the switch is activated. This is what allows the polarity reversal with only one set of power and ground wires running to the tailgate.

Adding a "supplemental" ground connection will not harm the setup but could well pinpoint the location of the faulty wiring. If the supplemental ground is run at the tailgate end of things and operating the window with the keyswitch improves but operating from the dash switch remains sluggish, the problem exists in the wring between the two switches and in this case the ground would be the ONLY wire that the two switches have in common since each switch has it's own power feed (circuit breaker).

 

Well, my window is also working slowly, and the dash switch isn't working at all... for all you guys have said so far, it must be a wiring problem. The motor is very old, but it seems to work fine.

 

there is a way to positively to see if it's the wiring causing low voltage, disconnect the motor from the harness and temporary direct wire a 12 volt battery to the motor,nothing fancy just wire to the motor and touch the other end to the battery,if the motor runs as it should then your wiring is the problem. I had the same problem on my 91,traced the trouble to the wiring that is folded at the bottom hinge on the drivers side, cracked insulation and corrosion of the wire. I wound up splicing in new wire on the frame just in front of the gas tank.cured my slow window. Also to reduce the drag that the window channel causes I sprayed silicone from a rattle can in both window channels.Works great. In the weather climate here on the gulf coast ,I have to recoat it about every 4 or 5 months. Hope this helps.
Kenny

 

Update: Finally pulled the panel off and did a check with the voltmeter today. Both wires into the motor (one for going up, and one for going down) were getting a reading of 12.7, so that told me my grounds were good. Frustrated, I put the window back together and closed it, but failed to get the wires out of the way. So, half way down, the window pulled the wires out and then stopped (obviously). The wires were set up with a slot and tab setup in case of this, so they pretty much just "unplugged".
After some work, I got the window out of the way by unbolting it, and then discovered that the wire for going putting the window up only had a few threads left. I cut and replaced the wire and it seems to have a whole lot more oomph. The hesitation when it would go up is gone.

Pretty pleased about that! I guess I'll see when it gets cold out if I'm still pulling it up by hand. Also greased up some spots that I couldn't access before because I had never taken the window out.

 

Old thread I know but I have some questions about the tailgate wiring!

For the wires coming out of the tailgate window switch, which ones are the ground wires? There are three wires for each switch, an orange/black, black/white, and purple/green for the down direction and then yellow/red, black/white, and purple/blue for the up direction.

I am assuming they are the black with white striped wires.

My rear window has always been kinda slow, especially in cold weather and I found this thread. I never thought about a bad wiring connection to be the cause but it makes sense. I took my window off and have the tailgate down, and when I hit the switch to move the "window" up, the motor works fine, but to move it down, it goes kinda slow. With the window off, I don't see there being any reason besides bad wiring for it to go slowly the different direction because there is nothing holding it back. I'm just having trouble getting the wiring out and trying to make sense of what is what.

Anyways I was thinking of making a new ground wire to see if that speeds up my motor but I don't want to splice it into the wrong wire...

 

Okay I found this diagram http://www.supermotors.net/getfile/6...otorwiring.jpg

So I guess I was wrong in thinking the ground would be through the black and white wires? I should just supplement a ground through one of the purple wires and see if that helps? I hope I'm understanding this correctly!