Tailgate switch bad?

11207 Views 15 Replies 10 Participants Last post by Scaglione, Sep 28, 2013

rdhayward

Discussion Starter · Oct 20, 2010

After hours of searching threads, reading the supermotors.net stuff, etc., I haven't found exactly what I'm looking for.

I'm dealing with a '96 FSB tailgate window: the switch in the tailgate (operated by key) doesn't work.

The dash switch operates the window up and down without any problems. The safety switch works fine (I've removed it and checked it), and because the tailgate switch seems to be wired between the the dash switch and safety switch, I believe there's a problem in the tailgate switch.

I've pretty much disassembled the tailgate, pulled all the wiring out and removed the black plastic wrapping, and there are no breaks in any wires.

There is voltage to both of the black/white wires within the tailgate switch, but I think they're getting less than 12v.

Pressing either of the buttons does nothing, not even a click, so I'm thinking that the circuits those buttons are supposed to open are stuck closed.

Is it possible that just the tailgate switch is bad, or is there something I'm missing?

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1 - 16 of 16 Posts

navynuke

· #2 · Oct 20, 2010

dunno, I'm in the same boat. Mine quit over the summer, have a spare one of those brackets, but have not had a chance to investigate it further. Bookmarking this thread.

Ken

Alvin in AZ

· #3 · Oct 21, 2010

rdhayward said:
...is there something I'm missing?

Yeah, a meter...

http://shop.oreillyauto.com/ProductDetail.aspx?MfrCode=MGI&MfrPartNumber=5898&CategoryCode=3389B
...using one would've saved you quite a bit of time.

Still not too late to use one since at this point, it can
find the trouble for you, if you give it a chance.

No kidding.

Alvin in AZ

rdhayward

Discussion Starter · #4 · Oct 21, 2010

I had less than 12v going through each of those B/W wires; about 8 or 9 volts, depending on whether the engine was running or not. However, there was a nice 12 to 14v at the circuit breaker #12.

Ran a jumper wire straight from the battery to the connector (underneath frame, behind the spare tire) and manipulated the buttons on the switch by hand, and it worked fine. The tailgate window motor plainly needs 12v and good amperage to work.

So the diagnosis is that there's a mild short, or perhaps corrosion or other problem causing resistance, in the wire between the connector and the circuit breaker. It was a lot of work finding this out, but it's nice to know that I've narrowed it down.

The switch and entire tailgate wire harness were practically new. The vehicle's owner had tried to fix the same problem by replacing all that, perhaps unnecessarily.

zerocool

· #5 · Oct 21, 2010

there might be a connector on the frame rail...

when i installed my new tailgate, i had a similar problem.
put in a brand new tailgate, but still had low/short power. i followed the wiring from the tailgate and found that there was a m/f connector on the right hand rear frame rail. (just keep following it back until it enters the cab)
i found the plastic connector was stock and the 3-5? copper pins were extremely corroded.
this also gave me reason to redo the entire stock wiring in the truck with a heavier gauge.

good luck

rdhayward

Discussion Starter · #6 · Oct 24, 2010

Thanks for the input.

I got under it yesterday to look for a bad spot somewhere in the black/white wire between the fuse (circuit breaker) #12 and the connector. I pulled apart the wire loom along the frame rail and checked voltage at a few places.

There was a bad spot in the wire just beneath the fuel filter. It looked as if something had worn or punctured the plastic coating, and the wire began corroding there. I cut the bad piece out and put in a butt connector.

Done.

cajunrebel

· #7 · Oct 25, 2010

rdhayward said:
There was a bad spot in the wire just beneath the fuel filter. It looked as if something had worn or punctured the plastic coating, and the wire began corroding there. I cut the bad piece out and put in a butt connector.

Done.

Wait... wait... wait... You spent all this time searching for the problem only to fix it with a butt connector? Take a few minutes and fix this right. That butt connector is gonna give you crazy amounts of resistance and cause way more corrosion than was already there. Take and solder in a repair and cover that in dielectric grease and heat shrink wrap it. That way it will last. There is nothing that I hate worse than shotty wiring repairs. I see em all day long at work (I am a fighter jet crew chief) and the electricians and avionics guys just cant seem to figure out why they have to re-fix their own repairs when they only half ass em.

choppers

· #8 · Oct 26, 2010

So I am new to FSB and I am working on a 1990 FSB XLT 5.8L V8. I have been reading all the threads about the tailgate issues and of course have the same problem.

When I push the switch on the dash, I don't hear anything, no motor sounds, nothing and now I can not open the T/G at all since the glass is up.

Can someone walk me through the steps they would take to track down what the issue is? I have read numerous posts on how to fix it once you figure out what the problem is but how do I know if its a short, the motor, regulator, etc.

•Jake•

· #9 · Oct 26, 2010

my tailgate switch quits once in awhile too. i just have to spray some wd40 in the key hole, let it sit and it works for a few more weeks... i wish i knew why.

Alvin in AZ

· #10 · Oct 26, 2010

Post #3.

"but, I don't know how to use a meter :/" -whiny voice
...just say so and then ask for help, silly.

Butthead in AZ
ps- Cool dots around your name, Jake.

pps- I don't know how to overhaul a V8 engine! (motorcycles, yes)
I don't think I'll ever learn how to overhaul a V8 engine. {shrug}
I don't see a real-world need for it in my case.
But learning how to use a meter is something -you will be- glad you learned.
No kidding, learn how to use one and your tailgate wiring problem/s is as good
a place to learn it as any. You can do it!

Get a better meter than the one I posted a URL to.
But the quality of the meter isn't that important other than it'll last you longer.
It'll be something you'll use over and over like most other tools.
Working on these old clunkers you'll run into electrical problems and the dangged
things are getting more and more "electrical" all the time too.

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El Kabong

· #11 · Oct 27, 2010

choppers said:
So I am new to FSB and I am working on a 1990 FSB XLT 5.8L V8. I have been reading all the threads about the tailgate issues and of course have the same problem.

When I push the switch on the dash, I don't hear anything, no motor sounds, nothing and now I can not open the T/G at all since the glass is up.

Can someone walk me through the steps they would take to track down what the issue is? I have read numerous posts on how to fix it once you figure out what the problem is but how do I know if its a short, the motor, regulator, etc.

Please excuse the cut & paste, but I'm beat & the info is in there.

El Kabong said:
3- How do I fix my back window?

The stuff below is mostly cut & paste from an earlier reply, but it covers a lot of tailgate window stuff. Use what applies to your situation.

Be aware that:

-The tailgate latch switch on the driver's side seems to be a common problem, check it early. It keeps the window from being moved when the tailgate is open, & if not latched right, it'll keep the window from working at all. Try pushing the driver's side of the tailgate in while holding the button or key switch in the up or down position. If that makes it work, check out Steve83's "How to align a Bronco Tailgate" link in #6 below & JKossarides info on door striker bushings in link #7 below.

-Ground for the motor connects up front, & at rest runs from there through both switches & both wires to the motor.

-When either switch is operated, 1 side's ground is disconnected & replaced by hot at that switch.

-Ground for the motor is not connected to it's case, but supplied through the wires.

-There are 2 seperate power sources & 2 fuses/circuit breakers for positive. 1 for each switch.

-The same 2 wires are used throughout for both up & down (Polarity is reversed by the switches).

-When the tailgate is open, you have to close the driver's side latch for the window to operate. Remember to open it before closing the tailgate.

Some good resource links:

1-Fireguy50's wiring diagram, see post 2. Great color diagram for 80-96s, it makes it much easier to understand what's going on.

2-Tailgate WIndow Wiring Diagram miesk5 provides a diagram for 78-79s by the ORC Staff at ford.off-road.com in post 3

3-Steve83's Tailgate Tech. Great pics & info. Look through the entire section for the portion that applies to your problem.

4-adrianspeeder's pics (He's doing torque pins for a passenger window, for the tailgate you don't need to drill).

5-Torque pins, motors, etc.

6-Steve83's How to align a Bronco Tailgate

7-JKossarides' info on replacement striker bushing numbers & wiring harness issues -See post 3.

8-Fireguy50's Re-wire your Tailgate window switch (FINISHED) Upgrade diagram using relays.

Testing:

Does it make any noise at all? Like the motor's turning, but the window doesn't move? If so, there are torque pins in the motor's drive gear that commonly break & aren't too bad to replace. See the torque pin, Steve83's Tailgate Tech, & Adrianspeeder's links above. If it makes no noise, then it's probably in the electrical system. Fireguy50's wiring diagram is linked above.

To test the electrical system, remove the access panel from inside the tailgate. Run test wires from the battery directly to the window motor connector (Yellow & red wires coming right out of the motor) to confirm that the motor works. To lower the window, it should be positive to red, & negative to yellow. Be ready for the window to move, keep hands & wires clear. Make all the connections but 1, then connect & disconnect the last wire quickly to see if it tries to go the right way. If it tries to go the wrong way, reverse the wires (This also makes it so that you can lower the window & get the tailgate open to continue testing).

A- If it runs & the window moves when wired directly to the battery, perform the following tests:

A.1- With both switches at rest & the latch switch closed, connect a tester between the positive test wire from the battery & each wire from the tailgate loom at the connector for the motor. Both should read 12v. If they do the ground is good. If they don't, refer to Fireguy50's wiring diagram linked above to trace it down, or tell us what you find.

A.2- With the latch switch closed, connect the tester between the negative test wire from the battery & each wire from the loom at the connector for the motor. The red wire should read 12v when either switch is in the down position, the yellow wire should read 12v when either switch is in the up position. If they don't, refer to Fireguy50's wiring diagram linked above to trace it down, or tell us what you find.

A.3- If everything tests ok, but it still doesn't run, there's a couple more possible causes to check:
-Sometimes the connector for the tailgate motor will test ok, but not make contact when plugged in. You might try backprobing the motor side wires with the plug connected. On mine I removed it & soldered the connections.
-It's possible for a damaged wire to carry enough load to show 12v on a tester, but not enough to operate the motor. Look for worn areas, especially in the loom between the body & the tailgate.

B- If it runs but doesn't move when wired directly to the battery, in addition to your electrical problem, the torque pins in the drive gear are probably broken too. Run the electrical tests in section "A" above, & see the torque pin, Steve83's Tailgate Tech, & Adrianspeeder's links above for the torque pin replacement.

C- If it doesn't run at all when wired directly to the battery, it sounds like it's time for a new motor. See Steve83's Tailgate Tech link above & use the info for removing & replacing the motor.

On my truck there were multiple bad connections, so it was hard to isolate the problem. Someone before me used a ton of crimp connectors :doh0715:. Basically I ended up removing them & soldering all the connections, & eliminating the corroded plug to the motor.

choppers

· #12 · Oct 28, 2010

El Kabong,

No need to write that out again and again. Copy and paste is perfect. That is exactly what I was looking for. A comprehensive troubleshooting guide.

I will be working on the truck this weekend and hopefully will be able to pin point the problem. I have already tried pushing in the drivers side of the tailgate while turning the key but got nothing. I don't hear the motor running at all so I am going with electrical.

I am going to run a 12V to the motor directly and see if this helps. To do this do you guys simply bypass the key and switch or run wires directly from the battery to the motor or use a spare 12V with direct connectors?

Thanks again for the detailed steps. I can work on an engine all day long but electrical stuff scares the crap out of me.

El Kabong

· #13 · Oct 29, 2010

I run both a ground & a hot directly from the battery. Since they're not fused, be careful to not touch them to anything or each other. It's not a good setup for a permanent fix, but it's ok for testing.

choppers

· #14 · Nov 2, 2010

I had a spare battery in the garage and took it to the back of the truck attached the wires and the window came right down. I know it's not the motor. After pulling the panel, I could see someone had done some work as there were some electrical twists used to secure the wires going to the motor.

Now to test where the break in power is coming from.

Any advice for how to test the wires between the rear key access and the main switch in the cab? The only access area I could see came out from underneath the rear, drivers side taillight but it was well wrapped and I would prefer to not cut into that.

I also pulled the rear panel off on the drives side but see that wires run through the rear fender panel.

I will start testing this weekend based on the list above and keep you posted as to the results. Thanks

Poppa5668

· #15 · Sep 28, 2013

Anyone know where I can get a replacement tailgate window switch ?

Scaglione

· #16 · Sep 28, 2013

don't know if it'll help but my dad and i installed a new rear window motor from bronco graveyard and it didn't want to go up at all. so we ended up running a piece of copper wire to the safety mechanism and basically made it a loopback if that makes sense.... so we could roll the window up with the tailgate down. I forget what it's actually called but I remember looking at steve83's stuff to troubleshoot. but that was the problem... I'll try looking for the picture

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