The tailgate limiter pin-switch is on the driver's side tailgate latch behind the tailgage window channel.

I will post pictures later but when the pincers on the driver's side tailgate latch close on the door frame striker pin, they activate a lever which pushes in the pin-switch closing the circuit to tell the system that the tailgate is closed and it is safe to raise the window.

Here's the deal:

After going to Pick-N-Pull on the hottest day of the year with my pin-switch in hand, I realized that I didn't have an electrical problem, I had a mechanical problem.

If the door frame striker pin is moved too far forward (e.g., because I want the tailgate to close tightly) the latch pincers don't close around it fully, and if they don't close around it fully, the little lever in the latch which pushes in the pin-switch doesn't get deployed so the tailgate switches think that the tailgate is down and it is unsafe to raise the window.

Using the appropriate torx bit, I moved my door frame striker pin aftward 1/8" and voila the tailgate window works!

I think this may be a common problem for those who have ohmed out their wiring and switches and still can't find their mystery "electrical problem."

It is not an electrical problem at all. It is a mechanical problem.

Since I had everything disassembled I lubed the tailgate latch with white lithium grease.

Here's how you get to it if you want. Remove the tailgate access panel. Disconnect the motor plug (in the center of the tailgate) and jump it (pos in one receptacle neg in the other, reverse if it doesn't go down on the first attempt) to get the tailgate window down. Then open the tailgate. Then jump the motor again to raise the tailgate window when the tailgate is in the horizontal position (support the window with two stools so it doesn't break off when horizontal).

Carefully remove the little bar which attaches the tailgate hand release lever which is at the center of the tailgate inside near the top. Remove the two hex head bolts that hold the tailgate window channel on the driver's side. Push it aside. Remove the three Philips #3 machine screws attaching the latch to the tailgate. Turn the latch so that the plug to the pin-switch is through or next to the hole where the latch was and carefully disconnect the plug. Remove and inspect the latch and the pin-switch. Lube the latch mechanism. Do a continuity test on the pin switch while fully extended (i.e., circuit open) and with the pin pushed in (i.e., circuit closed). If your switch is bad. Head to Pick-N-Pull or to your favorite BroncoGraveyard.com

Hope this helps!

 

Hmm just a thought, wouldn't it be easier to just bypass the whole safety pin switch? I understand it was there for a reason but unless you're in a huge hurry and not paying attention, I would think you would get it to close all the way. Just my thought on the subject.

 

Hey GruesomeJeans! I have read your threads on this issue. Bypass is certainly possible, but idiot limiter switches are made for people like me and I prefer to restore rather than redo in most situations.

As far as adjusting the door, the oem manual states many times that if a door is out of adjustment don't try to use the door frame striker pins to adjust it. Use adjustment shims on the hinges.

My door is adjusted properly, and I think it isn't out of adjustment by moving the door frame striker pin aftward by 1/8".

As far as what is easiest. Moving the driver's side door frame striker pin aftward a smidge should be the first thing to do before even opening up the access panel. That is if you can get the tailgate window down without having to jump it -- if jumping is necessary, the tailgate access panel would have to be opened to get to the motor electrical connection.

 

I see I see, that makes sense. My 78 is a bit different, I've removed a lot of things that were oem from factory. Before I got it there was a lot of problems that I've fixed most of. Originally my tailgate didn't even latch, the PO installed some shoddy latches on the exterior which he claimed was to "keep it from rattling when he went camping".. Turns out the latches didn't even work at all. I've since gon in and fixed them so the passenger side fully locks in but he driver side only locks in one click. I need to purchase a new latch for that side.

Anyways it looks like you've figured out what needs to be done to fix a pretty common issue.