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66-96 Ford Broncos - Early & Full Size
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M1llionb

86 Bronco fuse box/ Rear window

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Can someone please help me with a fuse box diagram? I've tried google, but not sure if they are reliable sources.

Long story short, I'm trying to troubleshoot why my rear window won't go down. 

 

FYI, I'm not an electrician, I'm not a mechanic. 

 

Thank you

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I just went through this with my '86 Bronco.  Jumped the wires in the tailgate to make sure the motor/regulator work and they did.  Come to find out, the wiring that runs from the HVAC window switch to the tailgate has degraded so much over the years it does not send enough power to control the window anymore.  Sucks.  I really do not want to take body panels off to fix that wiring...  Hopefully you have better luck than I did!

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I just went through this with my '86 Bronco.  Jumped the wires in the tailgate to make sure the motor/regulator work and they did.  Come to find out, the wiring that runs from the HVAC window switch to the tailgate has degraded so much over the years it does not send enough power to control the window anymore.  Sucks.  I really do not want to take body panels off to fix that wiring...  Hopefully you have better luck than I did!

The wires don't run under panels, they run along the frame under the truck. Key failure points are the connectors, and the cable between the rear door and the left tail light cavity.  If worse came to worse replacement with three new auto grade 14 or12 gauge wires would not be too difficult.  The reason for using 14 or 12 gauge is that it will keep the voltage drop to a minimum which will be better for the window motor.

 

If you have sluggish operating window motors it is most likely caused by voltage drop caused by corroded connectors or wires that are mostly broken from flexing where they transition from the body to the door, a common problem in old wires.

 

:)>-

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The wires don't run under panels, they run along the frame under the truck. Key failure points are the connectors, and the cable between the rear door and the left tail light cavity.  If worse came to worse replacement with three new auto grade 14 or12 gauge wires would not be too difficult.  The reason for using 14 or 12 gauge is that it will keep the voltage drop to a minimum which will be better for the window motor.

 

If you have sluggish operating window motors it is most likely caused by voltage drop caused by corroded connectors or wires that are mostly broken from flexing where they transition from the body to the door, a common problem in old wires.

 

:)>-

Thanks Seabronc!  I'll check that out when I get a chance.  It's tougher to work on the ol' Bronco now that the wife and I moved to Brooklyn!  LOL.  But, I love wiring and soldering.  So since the wiring runs along the left frame rail, this shouldn't be too hard to pre-fab up before the install.

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Last night, I tried working on this issue again. Upon me connecting the wires under the rear bumper, the window sounded like it wanted to move.

Rear Window cable 1

I also noticed the voltage also dropped, which caused my bronco to turn off. I took pictures, to make sure I'm not missing anything. The cables seemed a little corroded.

Rear Window cable 2

Can I get help, guidance on replacing them with 12 or 14 gauge? Also, inside the bronco I noticed this gray plug not connected. Is this for the defroster? 

Rear Window cable

 
Thank you

 

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Good morning,

So I was working on the rear window again... I jumped the window and it went down. GREAT! The motor works... now I can not get it back up haha.

I was told the tailgate I have is from a 94-96 bronco. Also, there's cables that are not connected...

Bronco Tail Gate Cable 2

 

Bronco Tail Gate Cable 1

I'm assuming since the tailgate is for a different year, the previous owner made modifications to the cables. I've attached pictures for reference.

Bronco Tail Gate 0

I appreciate any help!

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Yo,
Could be for glass defoster grids.

Can't view wire colors or where they are with my eye issue.

Are pics on driver side of tail light assy and tg?

 

86 Bronco Wiring Diagram by Gary;

9318405.jpg?1000

 

Good tech info;

 

Troubleshooting Synopsis;  by Seabronc

 

"...The tail gate circuit is pretty easy to resolve with a meter. Attached is a diagram of the circuit. Note that there are two fuses which you may have already found out. One powers the dash switch which is powered only when the key is in RUN or ACC. The other powers the tail gate switch and that line is hot at all times. If the motor is definitely good, (which can be verified by using a set of jumper leads directly to the motor connector). Once it is verified that the motor works then the common problems are: 1. The Latch Safety switch in the left side latch, This is often a problem when the tail gate fails from both switches.(you can pull the connector and jumper it out, which many people leave permanently jumpers out). The problem can be as easy as the latch needs adjustment. So if the jumper makes it work then either leave it jumped, adjust the latching stud for a tighter fit, or replace the latch switch if testing indicates it is bad. The function of the switch is to make sure the tail gate is latched before putting the window up. I like it bypassed because it makes it easy to get the window out of the way when working inside the tail gate. I think I'm smart enough to put the window back down before closing the tail gate . The only suggestion if leaving it jumped is to support the window if it is in the up position with the tail gate down. Else it could be broken by someone leaning on it. 2. The ground return for the tail gate switch uses the same two lines the dash switch does, (the grounding point is under the dash. The dash switch changes the function of the two leads running to the tail gate window motor by grounding one and putting 12V on the other. The tail gate switch uses the two leads for the ground connection, (it requires the dash switch to be in the neutral position in order to work). Depending on the year of the truck there are 2 or 3 connectors involved that often get corroded, sometimes to the point that the wires break off the connector. In your truck, there is on connector behind the left tail light, the next common failing connector is the one on the left side of the rear frame crossover member, (it is gray, if you can still see the color, and just under and behind the bumper). So to make it short, if you can operate the motor with a set of jumper leads and the window goes up and down that way, then the problem is a connection or the Latch Safety Switch. If you can't get the tail gate open to work on it, crawl in the back and remove the tail gate panel and find the motor leads attached along the bottom edge of the opening. Disconnect them and use a long set of leads or another battery in the back with you to test the motor. Once the window is down you can open the gate to make it more comfortable to work on the problem. In the diagram you will see a black with white striped wire that goes to the tail gate key switch, you should have 12V there at all times. To get at it, you will need the window in the up position. The other two leads, (with the dash switch in the center position) should indicate that they are grounded when doing a continuity check of them). You can also check the entire path from dash switch to the tail gate key switch by using a meter and probing the wires the purple with light green stripe and the dark green with light green stripe. Have someone (with the key in RUN or ACC) moving the Dash switch from UP to Down while you check those leads for 12V. If you don't get 12V then the problem is in a connector between the two switches or a broken wire (a broken wire would most likely be where they transition between the body and tail gate due to constant flexing). The procedure would be; 12V missing on one of the wires, move back to the connector behind the tail light (missing there), move to the connector on the cross member (missing there) move back to the connectors in front, until you find where you have 12V on the line you are probing. Once you find 12V the problem is between the last point probed and where you find 12V..."

  ...

if you hear teh motor spinning when it won't go up suspect the Motor Torque Pin:

 

Motor Torque Pin (also called Bushing) Info & pics; "...A cheap, quick, & reliable repair for most Ford window motors is to replace the degraded Delrin bushings in the motor's drive gear with common 1/4" nuts (thread pitch doesn't matter). Grease is only necessary on the central shaft & the outer plastic gear teeth - not in the pockets where the nuts go..."

 

Motor Torque Pin (also called Bushing) Info & pic; "...Dorman HELP part number 74410..." 
IMG_0020.JPG

Source: by Sixlitre (Malcolm H, Eddie BaBaBaBaue

 

Motor Torque Pin (also called Bushing) Info & pic; "...fixed it for free some fuel line and a few small cunks of a bolt. Here is a closeup of the bad parts. in the points of the triangle there should be 3 round pins. this help cousion the window from motor shock. I cleaned all the old grease out of the motor and the final drive. my final drive was fine so i was going to reuse it. To rebuild for almost free here is all you need. some fuel line and some steel rod or round spacer (this keeps the fuel line from colapsing completely) i cut the fuel line to the height of the drive gear housing and cut the spacers from round stock i had on the bench. the steel spacers go inside of the rubber fuel line. then the rubber fuel line and steel spacers go in the final drive gear.this was a tight fit but not too tight..." 

Source: by Michael C (collinsperformance, The Money Monster) @ http://www.supermotors.net/registry/6364/52803-2

...

Motor Torque Pin:

"remove the motor, and get a motor repair kit from the auto parts store. Replace the guts of the motor. simple 10 min fix.
Remove the access panel, and unbolt the 3 bolts that hold the motor on.
motor-bolts.jpg

support the window, then use a center punch on the motor shaft, and use a hammer to drive out the motor, if it doesnt slip out easily. you need to support the window so it doesnt fall on your hands.
TG Motor shaft circled in red
tg%20motor%20shaft.jpg

when the motors out, just slide the window down manually, open the tailgate so you can work on it easier.

get the repair kit, available at most auto parts stores
remove the cover to the gear box, remove the gear and clean out all the broken motor guts, replace with the new spacers and the new gear, grease thoroughly, close up the gear box, replace motor."  by Jer.

...

 

 

Ford does recommend, "Use Silicone Lubricant C0AZ-19553-AA (jelly) and D7AZ-19553-AA (spray) or equivalent meeting Ford specification ESR-M13P4-A on the door and window weatherstrips whenever necessary. Silicone lubricant helps avoid weatherstrip squeaks and retards excess weatherstrip wear from chafing between the door glass upper frame and the weatherstrip. It also helps to retain door window alignment by reducing friction between the glass frame and the rubber weatherstrip. Use Multi-Purpose Grease Spray D7AZ-19584-AA or equivalent meeting Ford specifications ESR-M1C159-A and ESB-M1C106-B to lubricate door and tailgate hinges. Apply an even coat to all hinge pivot points as outlined in the maintenance schedules or when a binding or squeaking condition occurs..."

miesk5 note, test the silicone on a regular styrofoam cup first; if the cup gets funky or melts, then the can or tube contans oil, a regular occurrence now, esp if from China.

apply dry (Teflon) lube to the flocked surfaces that touch the glass; dry lube prevents noise & abrasion, and allows the glass to move faster; take off the TG access cover and spray Tri-Flow in the tracks on either side so the regulator toggles slide up and down easy" by JKossarides
 

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miesk5,

Finally had time to look into it further... The pictures are from the driver side of tail light.

The tailgate is from another bronco, I believe from a 95 model.

I jumped the cables with a battery in reverse which allowed me to put the window back up.

 

How do I connect my cables from the tailgate to the rear window switch?

 

Thank you

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Yo M,

Use this to test the in cab-switch:

 tgmotorwiring.jpg

b Steve

 

To apply batty voltage to the cab rocker switch, use the C274 "Gray Master Tailgate Window Switch colors for up or down.

Or just follow the test instructions so that there are no accidental electrical issues. 

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