3rd gen tailgate woes

[Chaplain]

My window stopped working this past summer as did the wiper and I've noticed the defrost doesn't work anymore either.

The entire rear window, wiper, washer and defroster are on a fairly complicated interlock circuit. The rear wiper, washer and defroster will not work if the rear window is down at all (or the limit switch *thinks* the rear window is not fully closed). Obviously the wiper would tear itself right off the back of the truck if it were allowed to turn on while the window was partially open. I would start by checking the rear window limit switch. I know where it's located on a 2nd gen but not a third. I think your tag light is a separate issue.

I agree with you about the tag light since the time frame of it not working and the other issues is months apart. My "fix" stopped the battery from draining but removing the bulbs only put off fixing the root of the problem. I'm guessing a grounding issue somewhere??? On said wiring diagram does it show where the ground is suppose to be back there??

Regarding the tailgate window/deforst/wiper not working I'm at a loss. I have bench tested the window motor and it test out fine. The box makes a click and I've replaced it too. I'm not sure how to test the rear window limit switch or where that even would be?
Thank you for your help.

[Chaplain]

Also, sometimes the dome light works when the hatch is opened, but most of the time it does not. It always works when switched to the ON position.

[4x4mike]

Many of the grounds are common throughout the vehicle and I believe the ground wire for the limit switch and courtesy light are grounded within the back door ecu. There may be a frey or disconnect somewhere causing the tag lights to ground and stay on.

As for your defroster, wiper and washer the ecu thinks the window is down or maybe defaulting that because it doesn't know where it is. The limit switch is a 2 prong switch so it's probably a simple in and out and easy to test with a DMM. The wire out of the ECM to the switch is red with a light blue stripe, the wire comes out of prong 13 (upper right). That wire goes to the switch and a black and white wire comes out of the switch. I think that when the switch is closed there is continuity through the switch and it grounds everything. Test the wire on each side of the switch in relationship to continuity and ground. The wiring diagram isn't perfect in showing location but the limit switch is right next to the back window motor. It near where the door and lock latch near the bumper and like I said the switch has the red-light blue wire going in and a black and white wiring coming out. Other than that I have no idea what it looks like.

It sounds like I have the same problem you have regarding the dome only working some of the time when turned to DOOR. This is problem I'll try to fix and take pics of although it might be until the weekend. I believe it's similar to your limit switch issue but instead of the limit switch it's the courtesy switch.

[brian2sun]

Mine does the same exact thing as yours 4x4mike, except it's never stayed on with the door closed like your did. The light just doesn't usually come on when the selector is in the "door" position on mine. I believe the sensor/trigger (whatever it's called) is located in or maybe even integrated into the door hinge. There is also wiring going through that area that I was thinking could maybe get broken since it looks like it gets bent a little when the door closes.

[4x4mike]

The factory wiring is protected pretty well so I doubt anything freyed or was pinched unless you modified the wiring or harness. When I get the time I'm pulling everything and am going to attack the switch and go from there.

[4x4mike]

Had some time today to stand out in the cold and figure out what was going on.

I'll start with the defroster. I pulled the rear hatch panel and then a smaller metal panel on the passenger side of the hatch.



Smaller panel


Once the smaller panel is off you can see the bottom of the glass and where the wire connections are. I rolled the window down half way to make it easier to work on.

Right off the bat I saw this.



The connections to the glass seem to be glued and this one was no longer attached to the glass.





Here you can see that the defogger has a white and black wire to it and a black wire to it. It was the white and black that had come off.



I decided to check if everything still worked so I clamped it to the glass.



Still worked, or so I gather. It was warming up and this is my breath on the glass. I couldn't get a temp reading on it with my IR temp gun because it was all glass but visually it was working.





Since it was working, I think, I mixed up some epoxy and globbed it on. We'll see if tomorrow morning it really does work.

[MTL_4runner]

Nice find, that's definately your issue for sure. I probably would have used something conductive and waterproof like JB Weld instead of regular epoxy. My experience has shown that often regular epoxy comes apart when exposed to water (unless it's the waterproof type). Might be worth redoing before you put it all back together. Use a dremel wire wheel to prep both surfaces if you have one.

[4x4mike]

I thought of JB weld but the entire pad has definite spots for each wire. After talking with a glass shop they said use a resin and not JB weld. The JB weld would bled over to the black wire and short it out. This morning wasn't cold enough to test the window out.

[MTL_4runner]

Yes, JB weld is conductive so you'd need to be very precise about putting it on there or it would bleed current.
Just be sure the epoxy you used is waterproof or use some RTV on top of it to keep the elements at bay.

[4x4mike]

The glob from the factory covers 2 prongs from the black wire and the 2 you can see on the white-black wire. There is little room in there to keep it all together but there is some room for a dremel. The epoxy doesn't say waterproof but it's the same stuff that holds my rock lights together. Those are hanging low on the frame in the elements and have even been submerged.