94 Bronco power window issues (all windows)

[TrevorPiggott]

Posting for my brother who is running on no sleep and desperately trying to make his deadline.

Yesterday all 3 windows in my brothers 94 Bronco were slightly functional. All would get very brief power with the initial tap of the window button (window would move up/down slightly) but then nothing. Today when any window button is hit, nothing happens. No motor sound. No movement.
Any suggestions?

[Rmc]

http://www.supermotors.net/registry/media/834106_1

Link to fusebox diagram. Is the battery good? Verified i mean? Both positive and negative terminals, vehicle ground confirmed ? Those thing are constant voltage on both legs and drop a leg to ground to reverse polarity for motor rotation foreward vs reverse. So the side that drops determines which direction . Another thing to check is switches vs master switch (passenger, and tailgate key switch vs driver door). Trying to establish if it's a single switch or just the drivers door master control switch assy.

Keep in mind I'm not an auto electrician so I'm just throwing ideas out there. I just seem to remember both legs high ( voltage present) when I was poking around with a similar issue a while back.check each side of the switch to bare metal some place. If juice is present after switch is toggled on both sides it's not going low or bridged to the zero or negative volt circuit aka ground.

So in essence if any part of the zero volt side has no continuity to ground the voltage can't seek ground via the switch. As I recall there's 3 wires per switch, 2 hot one zero volt. See you chase a dead short ( positive voltage supply line brake or short to ground that blows fuses) or a zero volt short or partial short ( zero volt supply line)
Now that I've mentioned a partial short that would represent positive voltage leakage into the zero volt side, like a bridge between the positive side and zero volt side but only allowing a small amount of juice to stray from positive to negative reducing the negatives total value. The only reason a motor rotates in the first place is the positive voltage trying to meet it's equal or greater equivilant on the negative side to become absolved or absorbed. When too much positive leaks into the negative motion can't occur because the potential equalization isn't there.

[Rmc]

The positive has to be clean ( no voltage or amperage loss from the battery or alternator) and the negative side has to be clean (no positive voltage value present) if ground value ( total ohm resistance value) becomes " short or shorted" it directly translates to the positive voltages equal consuming counter part ( negative, zero bolt or ground) dosnt have a great enough resistave value to consume the positive voltage thrown at it.
Think of it as leftovers... No short =no leftovers, partial short= partial leftovers, zero volt short= everyone's too full to eat so it's all leftovers and the voltage present at that exact moment has no place to go to be consumed because everyone's already full off the supply feeding them before the meal.

Meal meaning switch actuation, leftovers meaning total positive value not being consumed after going through the motor because it found a way around the motor aka short path to equalization or ground resistive value.


Good luck.

[1971Ford]

Thanks fellas, i haven't tested much as the voltmeter is dead, but have played with it a little tonight.

I pulled the access panel off the tailgate and pulled the plug off the latch safety. Made a nice jumper wire and now don't have to worry about that being a part of the problem.
I also checked all the fuses, they are all good, made sure the dash switch was plugged in tight, and searched the dash harness for any possible bad connections or mystery wires. Couldn't find anything.
Pulled the switch panel deals out of the doors, nothing odd there either.
im not sure what it was... likely just random... but the driver and passenger window are back to barely moving, instead of doing nothign at all.
The tailgate window worked with the key for me once, but after i let it go back down all the way it wont do anything again at all.

Also, my dash/cluster lights, and fuel gauge all do not work. Taillights however do work. I've searched high and low but can't find any forgotten grounds or anything obvious.
Read that the dash lights share a common ground with the stereo, but i just tapped my stereo into the stock stereo's ground and that's been fine.

[philofab]

The tailgate windows and door windows are on separate circuits. I'm thinking there is an issue with the battery being moved or you are just unlucky enough to have three failing motors (unlikely).

Find the power window fuse and jump power there and see if that helps. That will help you zero in on the problem. I can't remember where the ground is for the window switches? Maybe behind the dash, see if you can verify ground to the switch.

[baja-chris]

I've found the bronco-era window switches to be unreliable, needing replacement every few years. They are cross linked so that makes them hard to debug. They are not too expensive, I'd put new ones in and if it still does not work then at least you know it's not the switches and you won't have to worry about switch failure for a few years.

[Wrightracing.net]

Ya. I converted my electric windows to manual. Every couple years it seamed either the driver's side switch or motor would have problems.

[Rmc]

The most common issues with the window motors is carbon dust from the brushes building up allowing a path around the armature vs through ( commutator to stator side? Or armature side? Meh just clean it, don't worry about what the thingymabob is called) So until you either reduce the carbon dust build up or crank up the juice nothing is going to happen with the motor. The other big issue is the bushing cup. I believe philo was nice enough to post up part numbers and a procedure some place.

For the first problem senerio, remove the brushes blow out with dust off reinstall and test. For the second find philos procedure in the tech section. The second senerio is mechanical resistance not electrical resistance.

[philofab]

Sadly, I forget I write that crap and only remember when I'm Googling how to do something and find my own how to.

[Rmc]

I could have sworn I saw a post that you showed the bushing cap and a part number ( was on the box laying next to the shot out bushing and the new one). I'm trying to remember. I think it was a rear window motor thread of some kind.

[philofab]

I could have sworn I saw a post that you showed the bushing cap and a part number ( was on the box laying next to the shot out bushing and the new one). I'm trying to remember. I think it was a rear window motor thread of some kind.

It was a driver window on my 93 F150. When the bushings go bad you can hear the motor run but it won't move the window.

[Rmc]

Ah I see.