80 series upper rear hatch turns on headlights and taillights and upper rear brake light not working issues

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landcruiser3DP

landcruiser3DP

Joined
Apr 9, 2017
Threads
352
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2,550
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tejas
troubleshooting EDIT: i pulled the two LED's in the vanity lights intern visors and this didn't fix anything. but i liked the 10A Dome fuse and now opening the upper rear hatch does not turn on the headlights and taillights. so i need to look at the diagrams closer to figure out what is happening?
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i'm continuing to troubleshoot an issue where i leave the headlights on at the stalk, take key out of ignition, open drivers side door - and if i open the upper rear hatch the headlights and taillights go on.
previously i had an intermittent issue where opening the driver side door did not turn off the headlights. then it became repeatable until i replaced the front (behind front row) and rear dome lights (behind second row seats). this seems to have solved the door opening not turning off the headlights.
initially this /also/ solved the rear hatch turning inthr headlights and taillights issue. however i subsequently accidentally blew the "Dome" fuse by trying to over one of these vanity LED's out of the visor (this fuse actually is in the same circuit for all the interior lights and the clock as far as i can tell) - and then when i replaced the fuse the upper rear hatch started running headlights and taillights repeatably (previously it was an intermittent occurrence).
i should note my upper rear brake light is also not working. the LIGHT itself was working when i hooked it up directly to the starter battery so my assumption is i am not getting power to those connectors even though i didn't actually test this.
just posting in case anyone sees any good ways to troubleshoot this or likes the idea of helping me break down electrical diagrams so i understand them.
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0. i have cleaned rhe ground contact below the center console.
1. i am going to clean the ground which i guess is up under the truck in front of the rear bumper?
2. i'm also going to pull the two front vanity LED's. and i will replace with incandescent when i find these bulbs at the auto parts store.
3. i'm also going to open up the fine lights and see if there is some frayed wiring or condensation on there.
> 4. anyone know how to get into the harness and connectors at the left rear pillar and in the upper hatch? i can't see how i am getting into that pillar or how i get into the upper rear hatch?
thanks for any guidance on this.

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how do i get into this harness at the upper rear hatch or the left pillar? i pulled on that headliner but dont want to crease it if i dont have to and i guess i yank the plastic off from the lower area all the way up to the rear seats?
i really don't want to do any damage so could use the advice.

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there are two remaining LED's in the vanity lights in the sun visors. i am going to hold that switch closed and pry it out with my key or use some plastic or wood to pry it out and test the hatch turning on the exterior lights issue.



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Did you make any progress with this issue? Like you, my headlights come on when the hatch is opened (light switch is ON on the stalk) but this stopped when I removed the bulb from the rear most courtesy light.
I have spent some time today trying to make sure all the wires and connectors are OK and noticed that my high level brake light only works with the ignition off. As soon as I turn on the ignition the high level light goes out. The corner brake lights remain perfect. The EWD isn't giving me any clues on this one. :meh:
 
Irish Reiver said:
Did you make any progress with this issue? Like you, my headlights come on when the hatch is opened (light switch is ON on the stalk) but this stopped when I removed the bulb from the rear most courtesy light.
I have spent some time today trying to make sure all the wires and connectors are OK and noticed that my high level brake light only works with the ignition off. As soon as I turn on the ignition the high level light goes out. The corner brake lights remain perfect. The EWD isn't giving me any clues on this one. :meh:
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honestly nice to have company on this even though it's probably not ideal on your end. i cleaned the ground under the center console like you advised. i am going to clean the ground that shows in the EWD at the rear? it seems to be under the truck or maybe somewhere in the rear cabin area?
i'm also planning on removing the dome lights to see if there is any condensation there?
i was also told to inspect a part of the harness that goes through the firewall on the left hand side in right hand drive diesel rigs (is this right hand side in US left hand side drive?) because supposedly there are two pairs of wires (?) that are poorly connected and they get loose.
the other thing i haven't been able to get to is to inspect the harness at the upper rear tailgate and the left rear pillar? i didn't find an easy way to get the boot off at the upper rear tailgate (honestly i didn't try because i don't want to rip into anything) and i don't see an easy way to get into the left rear pillar (tried but dropped after removing one vertical piece of trim).
 
landcruiser3DP said:
honestly nice to have company on this even though it's probably not ideal on your end. i cleaned the ground under the center console like you advised.
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When I cleaned that ground (BF) I thought it can fixed my high level brake light however, at that point I had not noticed that the high level light worked with the ignition off so I claimed victory. Today I noticed it won't work if the ignition is on so no further forward.
landcruiser3DP said:
i am going to clean the ground that shows in the EWD at the rear? it seems to be under the truck or maybe somewhere in the rear cabin area?
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The ground at the back is BG and is physically underneath the truck and the back. The harness runs from the right hand rear light cluster then out through the quarter panel and along the rear frame. BG is smack in the middle just next to where the licence plate light breaks out of the harness to enter the lower tail gate.
landcruiser3DP said:
the other thing i haven't been able to get to is to inspect the harness at the upper rear tailgate and the left rear pillar? i didn't find an easy way to get the boot off at the upper rear tailgate (honestly i didn't try because i don't want to rip into anything) and i don't see an easy way to get into the left rear pillar (tried but dropped after removing one vertical piece of trim).
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If you pull the trim piece that holds the rear edge of the headliner, you can get access to the connectors for the upper hatch. You might have to remove the 3rd row seat belt and pull the cover off the rear pillar.

Last night I followed my daughter home and noticed nothing changed with the rear tail/brake lights when she came to a stop. The brake lights were either on all the time or only the tail lights were on. Today the brake /tail lights work perfectly. Scratching my head with that one.

So far I have tided up as much of the wiring as possible. I removed the trailer light box which has left me with a harness that is not connected to anything except for a single green wire that runs along the rear of the trunk under the carpet. I have not got to the other end of this wire yet. It don't look OEM but the same wire is on my '95 cruiser.

On the passenger side of where the BG ground is located, there are 2 connectors. One has 2 wires Green/Yellow & Green/Black. this connector is for the turn signals. No idea why it is connected this way. Right next to this connector is a similar connector with 3 wires but nothing is connected to it. One of these wires is connected to the brakes. I could not establish what the other 2 wires are for but since the connector is not used, I moved on. I am currently working on the drivers side of this harness and have found a white/black (ground?) that is broken but as of now I have not found the other end of it. My plan is just to work my way back through the harness looking for poor connections.

A reverse look up on the EWD would be nice - being able to see which circuits are in a particular connector would be really helpful.
 
I had this exact same issue with my 93 FZJ80. When I would open the hatch, my head lights would come on, and it acted like the keys were in the ignition. Other symptoms were a non functioning third brake light, rear defroster, or rear wiper. I fixed it by adding a new ground to the upper hatch. It's been over a year since I did it, and I don't want to tell you the wrong information so I will take picture of mine when I get home today.
 
VSTL said:
I had this exact same issue with my 93 FZJ80. When I would open the hatch, my head lights would come on, and it acted like the keys were in the ignition. Other symptoms were a non functioning third brake light, rear defroster, or rear wiper. I fixed it by adding a new ground to the upper hatch. It's been over a year since I did it, and I don't want to tell you the wrong information so I will take picture of mine when I get home today.
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oh. well the symptoms are spot on for the first two.
i just tried the rear wiper and it just clicks?
not totally sure how to test rear defogger.
anyway pics would be /great/. THANKS.
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i wonder if anyone can tell me where i find the fiat harness or how i get into the wiring that goes into the upper rear hatch? i a duality had to replace the upper rear hatch and i've wanted to check the pins for some time now.
 
My rear wiper just clicked as well. If you took a jumper wire and touched it between the wiper motor casing, and an unpainted part of inside the upper hatch, I bet it would start working. I believe that is the connection I made for my repair. I believe the ground in my upper harness was open or intermittent, instead of returning through that ground wire, I decided to return it through the body. After I did that, everything worked. I had already benched tested the third brake light, wiper motor, and checked the wiper control relay. My day job is a electrical maintenance tech, and I wouldn't repair it this way if it was for work, but good enough for a temporary fix. I'm pulling this all from memory, so I apologize if its not 100% accurate.

One last thing that would happen with mine, If I left the defrost button pressed in, and took the keys out of the ignition, the entire dash/blowermotor/radio would still be on. They would only turned off when I pressed the defrost button to off. It was really strange.

Edit: Use this as troubleshooting advice, not as a repair because it's definitely not.
 
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I had non functional rear wiper, and all lights would stay on if rear defrost was left on with out key. Two wires in the upper hatch harness were exposed and shorting.
You need to pull the trim off and check your harness.
 
secretasiansam said:
I had non functional rear wiper, and all lights would stay on if rear defrost was left on with out key. Two wires in the upper hatch harness were exposed and shorting.
You need to pull the trim off and check your harness.
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Edited my post a bit. This is 1000% how to properly fix the issue. Be better than me landcruiser3DP and repair it the right way :flipoff2:
 
Just wrapped up this episode. Dropped the corner of the headliner and got access to the 2 harnesses that feed up from the rear. Couldn't see any damaged wires but the wiggle test won out. Part of one the connectors had somehow broken and was making an intermittent connection. Not a lot of room to work with so I just cut the 3 wires from the connector and used some spade connectors.
The results are as follows :-
1) Rear courtesy light is now bright when the hatch is opened.
2) High level brake light works with ignition on and is proper bright.
3) Rear wiper works
4) HVAC controls turn off with the ignition key.

And the icing on the cake...drumroll please

The headlights no longer switch on when I open the hatch.

Big shout out to @VSTL and @secretasiansam for sharing their experience and solutions.


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