Circuit #1

[rollingpinz]

Last night, the #1 circuit breaker popped. So I lost instrument lights. I checked and left rear running light is out too. My license plate lights never worked(in case it’s part of that circuit).
I tried removing all bulbs(instrument, left rear running light, and the led butchery for the license plate)
No luck. Still trips breaker.
The left rear running light had black tinting, but the filament looked good. Also, there was a little corrosion.
Nothing looks out of the ordinary under the dash. I hate poking around in there unless I have a specific target.
What should I check next?

Side question, when I turn on turn signals, both top and bottom bulbs flash up front. Isn’t one supposed to be a running light?

[rmel]

Short hunting...can be a real PITA to nail.

Look for any possible locations where Power is close to a ground terminal
e.g. under the dash. An other place to look is inside the Junction box at
the rear of the truck. The routing of that lead in the trail section can get
a little funky.

[Hugues]

I had a short in my left or right running light.
One of the 24V terminal was touching a grounded metal part inside, was not obvious when I look at first. Sorry I can't find a picture. And my flasher were behaving weirdly.

[rollingpinz]

That’s funny you mentioned the flasher. My flasher was acting weird too. It stopped flashing and got hot. Now it works, but slowly. I can’t imagine how it would relate to the left running light. But I have been surprised before. I have a new flasher on order from SAV.
I’ll check the rear junction box tomorrow.

No matter what I did today, it didn’t feel like being fixed.

[rollingpinz]

So it was the license plate lights that caused the short. It was happening inside the body. I pulled the wire out and took it out of the tail light bucket.
Now the real challenge will be getting a new wire back through the body to power those license plate lights.

Side note
There is a cone next to where the wires go into the tail light bucket. It is welded to that panel and points towards the left rear tire. On the back side, facing traffic behind me, there is a small panel held in with 4 screws. What is this?
It’s not the trailer connection. That’s next to the trailer hitch

[ChickenPinz]

Do you mean this junction box?

IMG_20200229_165847 (Large).jpg (458.44 KiB) Viewed 2119 times

[rollingpinz]

No. The metal panel that the left tail light is mounted on. The cone is on the opposite side of that panel and points toward the left rear tire. It looks like ie was meant for a connection. I just don’t know what

[rollingpinz]

It’s just above the mudflap

[ChickenPinz]

I think you mean this one? That's for power.

Capture.PNG (242.76 KiB) Viewed 2109 times

[ChickenPinz]

here's a better pic

Capture2.PNG (1.14 MiB) Viewed 2108 times

[ChickenPinz]

And a pic to show the cup you're talking about plus a view of how I removed the reflector and installed a back-up light (low and high power). I use that power connector to provide shore-power when working on the truck, or to provide 24V output.

IMG_20200312_173015 (Large).jpg (289.21 KiB) Viewed 2106 times

[rollingpinz]

Yes. That’s it. Thank you.

[whitesik]

Many of you probably know this but that plug was used to attach the 24v generator to the 710k for radio operation when parked. It also has a hidden fuse link in the wire to it housed in that cone.

[rollingpinz]

It’s very odd. I have the large red wire that would go in there, but the connector has been removed. The wire is not connected to anything. There’s a plate held in with 4 tiny screws where the connector would be.