Shorted flashing in 3rd brake light on cab

Just noticed, irregular low level flashing short. Only detectable in dark. Certainly very recent. Truck is OFF. 22k 1 y.o.

How is this getting power?? Brake off, parking brake off, RedDArc tow controller activates a different wire and playing with it does not vary this issue.

Anyone else see this?

To access Ill need to pull caulked work cap and end up trashing expensive EPDM foam bedrail shims due to cold brittleness. Argh.

Not going to be successful in a warranty claim for incidental damages.

vimeo.com/1049881270/babade7a49

 

This is too weird.
Last night and this morning checked battery as concerned about drawdown.
13.8v running and 12.4v stopped which is normal.
Last night and this morning I noticed the truck started without hitting the remote kill switch fob.
I have a Mobilistics kill switch starter relay.
I've also looked for mouse damage to wiring, fortunately see no signs.

After a trip this morning in warmer weather (15F not 2F) everything seems back to normal. Keyfob start working correctly, voltage leakage to third brake light seems to be gone.
How would a stuck starter relay send low intermittent power to the third brake light?
Or was shorted power somehow running through the negative grounded frame?

 

Which was first, the shell or the remote starter?
Load test the battery.

 

The brake light on rear of cab was noticed first. I think the start relay kill switch coincides.
Neither is happening now.
Read up on load testing, killed off lights and draws, waited sixty minutes:
12.83v resting, 14.8 running/charging, 10.01v minimum on startup so battery is strong.
Clamp ammeter 0.56A resting so little parasitic draw.
Put the meter in the truck so if this happens again I can test.

What I can't figure out.... how was reduced flickering voltage getting to the cab third brake light and not to the rest of the brake light circuit?

 

I believe those lights in the 3rd brake light are LED's, which don't require as much voltage as the tail lights to illuminate.

 

"I believe those lights in the 3rd brake light are LED's, which don't require as much voltage as the tail lights to illuminate."

Good point, thank you. If/when this occurs again I need to check parasitic draw, and measure any draw at tail lights.
I put cheap LED lights on my construction trailers. Wonder why Toyota is still using bulbs and folks are spending $$$ on LED headlight upgrades.

 

Has not re-occurred. Gremlins. Have to chalk it up to the relays, or ice expanding a grommet and water creating a short circuit.

Can you imagine running a nuke plant and having this one-time shit occur....

Technician: we'll have to tear it down and diagnose. Don't want this happening again and getting into trouble.
Estimator (that's me...) : for the cost of diagnosis we could just replace it. Better to do it proactively, downtime is money.
Project Manager: hell we'll deal with it if it occurs again. No point wasting time now.
Superintendent: who the hell put that thing in in the first place! I'll rip his head off!
General Manager: nothing happened. No outage, no record. Go back to work.
Executive: put a flag on it and Make Lights Beautiful Again.

Don't you feel safer?
Glad I'm retired.

 

.56 Amps...or .056 MA

 

This is a problem with the Redarc brake controller. There have only been a couple people on TW that have encountered this problem.

https://www.tacomaworld.com/threads/strobing-third-brake-light.751482/#post-28327040

https://www.tacomaworld.com/threads/brake-lights-flashing-in-extreme-cold.747744/

For a yet undiscovered reason, the cold (15°f and lower) somehow affects the brake controller wiring and intermittently activates the third brake light. If the brake controller is unplugged (under the steering wheel) the problem immediately stops. Personally I tow a trailer for work frequently and unplugging will reset the calibration on the brake controller, this can be particularly frustrating and dangerous in the snow. I’ve not had the battery drain to the point of failure, but I really don’t want to get to that point, especially in winter. If anyone has any ideas, I’m all ears. I plan on owning this truck for many more years, and don’t want to have to worry about this forever.