91 FJ80- Rear running lights not working, everything else working (1 Viewer)

[JakeVII]

My running lights have stopped working at the back of the cruiser. That includes side reds, rear running light and license plate lights.

The ones at the front still work, and so do the brake lights, backup lights and turn signals.

The 15 amp tail light fuse isn't blowing, either. Any ideas?

 

[inkpot]

My running lights have stopped working at the back of the cruiser. That includes side reds, rear running light and license plate lights.

The ones at the front still work, and so do the brake lights, backup lights and turn signals.

The 15 amp tail light fuse isn't blowing, either. Any ideas?

Check inside the rear quarters for the trailer wiring adapter. It's a little box about the size of a pack of smokes. If the box dies, then it screws up yur lights. Usually on the right side. But not always.

 

[JakeVII]

Does a higher resistance necessarily mean I'm further from the line break? I'm getting 1.1 ohms on the right marker light and 4.0 ohms at the left (driver side) marker light. Also 1.6 at the licence plate bulb.

 

[JakeVII]

Two other things:
1) Practically no voltage when I test the affected bulbs. As in, almost nothing. A few mVs DC at best- less than a AAA battery and this is coming from a 12 V system.

2) I suspect the wire harness BQ1 FLOOR NO.3 WIRE AND FLOOR NO.1 WIRE (LEFT QUARTER PANEL INNER) as a possible culprit, but the thing's a beast. Anyone know how to get this thing opened so I can check it? It's all covered in ancient insulated tape and I don't wanna break it. A tip on how to open it without breaking it would actually be super helpful.
It *looks* good, but then again it's only one bad wire causing all this so I really can't go ruling anything out.

 

[jonheld]

Anyone know how to get this thing opened so I can check it? It's all covered in ancient insulated tape and I don't wanna break it.

Toyota uses foam tape to cover connectors to prevent rattles. Peel the tape off, clean up the connector housing, and separate.

 

[JakeVII]

The side of the plug closer to the front had a full 12V. The back side of the plug seems able to conduct electricity, too. Further down the line, the licence plate plug had no power. I suspect the power is grounding out somewhere between the licence plate plug and the BQ1 connector in the driver side quarter.

Is that something that sounds likely from an electrical perspective? I can read a multimeter and I understand that longer wire = more ohms, but beyond that I'm not an electricity guy.

I've also checked the ground in the frame behind the spare tire. I cleaned it off and it had no impact.

I'm slowly running out of wire to check, which is good I guess.

 

[jonheld]

I suspect the power is grounding out somewhere between the licence plate plug and the BQ1 connector

If +12 was being "grounded out" you'd be blowing a fuse. Likely an open rather than a short.
You are blindfolded in a dark room without the factory service manual. Do yourself a favor and get one for your truck.