97-FZJ80 BRAKE/TAIL LIGHTS DO NOT WORK,SIGNALS/REV DO WORK

[CMD]

I have recently had some issues with my rear lights shorting out whenever driving in the rain (none while parked in the rain). The front and rear driver's side turn signal would stay on and brake lights and other signals would not work. a few days later all lights would work fine. I solved that issue by sealing up the frame of the rear sliding window frames with black silicone sealant. However now my rear (red) lights do not work at all (brake lights even the red light bar in the rear window). I changed all bulbs in both tail light fixtures and I have no blown fuses. I will soon clear the cargo area completely and remove jump seats and rear side panels in hopes of finding the culprit.
Any help would be greatly appreciated.

1997 Lexus LX450

 

[Parsnip]

A hack job trailer wiring would be far from unprecedented.

 

[inkpot]

A hack job trailer wiring would be far from unprecedented.

Pull the right tail light assembly and inspect the trailer light harness adapter box and wires. Mine sheeted out and caused me lots of problems similar to yours. John

 

[CMD]

Pull the right tail light assembly and inspect the trailer light harness adapter box and wires. Mine sheeted out and caused me lots of problems similar to yours. John

Parsnip and inkpot, Thank you both for the input. I unplugged trailer light harness adapter box but the issue persists. I have discovered that the vehicle is taking in water from the rear passenger side door. I also cleared the water channels under the sunroof. I removed all panels from the passenger side. With the drivers side turn signal on I noticed it start to blink rapidly once I touched the wire running along the passenger side. I will have to return to this after later as I have to go to work.

 

[CMD]

Pull the right tail light assembly and inspect the trailer light harness adapter box and wires. Mine sheeted out and caused me lots of problems similar to yours. John

Once again Thanks, John and Parsnip. I found the culprit! The cause of the issues with my rear brake, signal and tail lights was a small electrical fire caused by water kicked up by the tires into the rear quarter panels where the wires are housed. The water caused an electrical fire with the body wire connecting to the rear lights (drivers side body wire behind rear wheel well).

 

[CMD]

 

[Parsnip]

Nice work, Detective!!! Well done.

 

[retrofive]

Nice job finding the source, but water sprayed up through the wheel well? (Unless I missed something I would think being a more common spot for water getting there is through the rear sliding windows seal.

 

[CMD]

Nice job finding the source, but water sprayed up through the wheel well? (Unless I missed something I would think being a more common spot for water getting there is through the rear sliding windows seal.

Thank you, retrofive. I removed the splash guards and factory bumper to prepare for an aftermarket steel bumper (but still can not decide on slee or 4x4Labs) therefore leaving these holes (one on each side) uncovered. This can also happen to anyone who drives in deep water or mud.

 

[retrofive]

Ah. I see.

 

[inkpot]

Any chance the fire was caused/ enhanced by heat from the tailpipe? That's what happened to me. I cut off the resonator a long time ago. On a trail run I bent the exhaust pip up so it exited right towards the bottom of rear qtr where all those wires were laying. It melted them so bad it even melted my right tail light fixture so much that the plastic ran into the tailgate hing so bad that it was basically welded shut. Boy, what a Mesa!!

 

[Tools R Us]

My guess, that wasn't caused by water dripping on it, would likely work just fine under water. Likely caused by a bad connection at that connector and/or a short/excessive load downstream from it.

 

[CMD]

Any chance the fire was caused/ enhanced by heat from the tailpipe? That's what happened to me. I cut off the resonator a long time ago. On a trail run I bent the exhaust pip up so it exited right towards the bottom of rear qtr where all those wires were laying. It melted them so bad it even melted my right tail light fixture so much that the plastic ran into the tailgate hing so bad that it was basically welded shut. Boy, what a Mesa!!

The fire was definitely caused by water kicked into the rear quarter from the tires due to lack of that plug and me removing the factory bumper corners as it would only short out when I drove in the rain (not when parked no matter how hard it rained.)
As for the exhaust pipe, it's on the passenger side where the tow wire box is. The heat from that pesky exhaust pipe has caused the rust to accelerate on the passenger side of the vehicle. I found a hold in the rear quarter passenger side, also rusted out the rear coolant lines. I ran a heater hose bypass for now (last fall). I will run a hose line to the rear heater when I get the time.

 

[CMD]

My guess, that wasn't caused by water dripping on it, would likely work just fine under water. Likely caused by a bad connection at that connector and/or a short/excessive load downstream from it.

Definitely caused by water as the lights would only short out when driving in the rain and not when parked in the rain no matter how hard it rained.

 

[jonheld]

I agree with Kevin. I think your cause/effect are reversed.

 

[lenross1]

I

View attachment 1100076 View attachment 1100077 View attachment 1100078 View attachment 1100079 View attachment 1100080 View attachment 1100078 View attachment 1100077 View attachment 1100077 View attachment 1100076 View attachment 1100076 View attachment 1100077 View attachment 1100078 View attachment 1100079 View attachment 1100080

know this is an old thread but does anyone know of the part number or what this harness is called. My 80 tail lights are doing the same thing.

 

[Squash]

Better check your rear drivers side as well.
Both my 93 and current 97 suffered the same problem.
I attribute my issue to road salt corrosion.
This is a slow process which we tend to ignore.
Remove the OEM jack and holder to get a good look at the harness under the jack, if you're lucky it's OK.
Otherwise maybe just some blue corrosion at connectors.

 

[MrMikeyG]

It looks like everyone has this sorted, but any chance a leaking window washer system could contribute to this as well?

 

[Benbmore3d]

Can anyone tell me what these hoses are for? Thanks in advance for any help.

 

[ZachS5811]

Is this plug on the driver or passenger side rear?