Bad Ground/exterior lighting issues? (1 Viewer)

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Wauconda, Illinois
My 97 FJ80 continues to blow the fuses for the turn signals, running lights, and brake lights. Head lights and flashers work. Has anyone experienced a similar issue? I’m assuming it’s a bad Ground and was wondering what/where the most likely culprit could be. Thanks for the help.
 
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A faulty ground wouldn't pop fuses, it would cause the lights to be dim or not work at all. You have a short somewhere.
Inspect the wiring harness that runs under the rear cross member of the frame. There is a factory plug for a Toyota trailer harness that will corrode over time and cause issues.
 

bajaphile

Boojum Hugger
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There is also a green unprotected wire that runs between the two rear tail lights that you can see if you remove the rear metal strip that holds down the carpet at the tailgate. That green wire will get chafed as it goes over a sheet metal section on either the passenger or drivers side quarter panel.

For me, it was the trailer harness control box which got wet after a rain and shorted out all sorts of things. I simply removed it (glued onto the rear passenger side wheel well, accessible by removing the plastic interior quarter panels) and all associated wiring. You can just unplug it all and pull it out.
 
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There is also a green unprotected wire that runs between the two rear tail lights that you can see if you remove the rear metal strip that holds down the carpet at the tailgate. That green wire will get chafed as it goes over a sheet metal section on either the passenger or drivers side quarter panel.

For me, it was the trailer harness control box which got wet after a rain and shorted out all sorts of things. I simply removed it (glued onto the rear passenger side wheel well, accessible by removing the plastic interior quarter panels) and all associated wiring. You can just unplug it all and pull it out.
What you describe is an aftermarket trailer harness. A stock truck has none of this.
 
Joined
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A faulty ground wouldn't pop fuses, it would cause the lights to be dim or not work at all. You have a short somewhere.
Inspect the wiring harness that runs under the rear cross member of the frame. There is a factory plug for a Toyota trailer harness that will corrode over time and cause issues.
One thing I forgot to also mention that led me to believe it was a ground issue is the right turn signal stays illuminated. And the door ajar indicator on the dash also remains illuminated.
 
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My LX has this trailer harness, marked Toyota, installed at the port. Stock.

The green wire crossing under the carpet is part of the trailer wiring.
Well, I think John means 'stock' as from Toyota Japan at the factory.

Port installed stuff is done by local monkeys and is no better (and possibly worse...) than 'aftermarket' :)

cheers,
george.
 
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Yep, pseudo off topic :)

For the OP:

All the brake/turn/park lights use the body as ground. So, as Jon stated, a bad ground would just cause dim lights or effects like turn signals causing pulsing in other signal lights.

To blow a fuse you have a short on the +12V side of wiring.

So, to confirm: Fuse is ok, then if you apply brakes it blows. If you turn on left/right indicator it blows (I assume you have key to 'on' in this case). If you turn on parking lights it blows. Doesn't blow if you turn on 4 way flashers??

cheers,
george.
 
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Yep, pseudo off topic :)

For the OP:

All the brake/turn/park lights use the body as ground. So, as Jon stated, a bad ground would just cause dim lights or effects like turn signals causing pulsing in other signal lights.

To blow a fuse you have a short on the +12V side of wiring.

So, to confirm: Fuse is ok, then if you apply brakes it blows. If you turn on left/right indicator it blows (I assume you have key to 'on' in this case). If you turn on parking lights it blows. Doesn't blow if you turn on 4 way flashers??

cheers,
george.
Correct
 
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Exactly which fuse(s) blow when you apply the brakes versus turn on park lights versus turn on turn indicators?

The turn indicators cause a fuse to blow only if the key is in the ignition 'on/run' position ?

You say your right turn indicator stays lit - is that with key to on/run, and that doesn't blow the fuse? Or only blows the fuse if you flick the right turn stalk?

There's quite an electrical maze of wires in a 'modern' land cruiser, so we need to know specifics to figure out the common area that would cause all this things to happen.

Do you have a trailer lights 'module/harness' ?

Oh, have you downloaded the free '96 EWD (links on this site)? It will be more than close enough for you '97.

cheers,
george.
 

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