Dash, tail, brake circuits out. Tranny shift lock engaged

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Sep 5, 2003
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Location
Yuma, AZ
Reference this thread from 2004:

https://forum.ih8mud.com/80-series-tech/23613-brake-tail-dash-lights-out.html

I am experiencing the exact same thing - also in a 1991 FJ80.

I did have a bad tail light bulb (could have gone bad when I was messing with it) but have replaced that. All marker lights flash when I activate the alarm - so they work, but only when the alarm feeds them.

I recently installed a trailer converter myself and haven't checked that yet, as it is late.

I found the tail light fuse blown at one point - put another in which blew immediately. As it sits now with good bulbs in it the tail light fuse is not blowing - but it is not getting power...

Fuseable links appear to be good.

Mr "Original Owner" has not posted since the day after the last post in the above thread. He also never posted up any solution that he may have found. Thanks for that. Thanks a lot. :mad:

I will start looking into this tomorrow at work I guess.

In the meantime, if anyone has any ideas please let me know.
 
Disconnect the trailer harness. There are several members who have had problems similar to yours, and remedied them by simply taking it out.
 
Disconnected trailer harness - no change.

pulled connector at brake switch (at pedal) because it was not making an audible click. Tried jumping the wires there but could not make brakes illuminate.

Fuses good.

At some point we notice the battery is low and I can no longer start the vehicle.

Check wiring at alternator and the main charge wire (pair of white wires) crumbles off in my hand.

Main Fuse link at battery end of charge wire also damaged - hanging on by half or less of its strands.

EWD does show that all circuits: stop, tail and dash illumination are sourced through this fuse link.

Maybe once I fix the charge circuit everything will come back?

Also - somewhere in all this the shift lock let go (returned to normal operation). This was after disconnecting the trailer harness but not sure exactly if that was it or not.

I cut off about 5" of the pair of white wires at the alternator and will splice some new wire there at least to get moving again. Will also get a new fuse link.

Any ideas? Am I moving in the right direction?
 
when i was experiencing the same problem on my 91 the clicking noise was a box connected into the brake lights behind the rear ps panel.... it ended up arcing all the way off and melted... so we took it out, bypassed it, took the trailer harness off and no problems since... hope that helps
 
:bounce::bounce2: F I X E D ! ! ! :bounce::bounce2:

The problem in my charging circuit obviously needed attention - and further research with the EWD showed that all of the affected systems draw power through the main fusible link - the one that was compromised.

After splicing in some new wire at the alternator and putting in a new fusible link everything is fine. Back to normal.

I have a couple words of advice:

1) Get the EWD and FSM for your vehicle. They are invaluable when troubleshooting your rig.

2) You might want to go out and check the connection at the back of the alternator - in my 1991 the exhaust manifold is close by and likely contributed to this failure. The wires themselves were brittle and corroded. Pry back the rubber boot and really take a good look at the condition of the wires.

I honestly don't know how this was working as long as it did. This took time to happen and I have driven across the country and did some hard wheeling just two days ago.

I'll be reconnecting my trailer harness now!

Here's the ring terminal and wiring from the alternator.

DSCF1128.JPG
 

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