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Epollan2000 · 10-29-2020, 03:23 PM

You guys were here for me when I was about to pull my hair out. So I thought I would share my solution to the problem. After realizing that my problem was in some way connected to the light switch, I pulled the 12v fuse to the lighting circuit. I traced it from one end to the other. Checking everything connected to the circuit. Turns out that one of the 12v fluorescent light fixtures in the bathroom had a short in the ballast. As soon as I unplugged the light fixture the problem cleared. The light fixture would still work, but was causing some sort of feedback on the grounding circuit that confused the transmission controller. I replaced the light and have since logged almost 1000 miles without a problem. Thanks again to everyone who replies to my first post.

Eric

Skip426 · 10-29-2020, 03:37 PM

Thank you for wrapping up you post , with good info on what you found to be your problem.

That has to be a weird one; a problem on a coach manufacturer circuit , with wiring in the ceiling , interfering with the an ECM in the chassis harness.

Could you post your, coach's chassis manufacturer and the Allison trans ECM location .

I like to keep track of the really weird electrical issues and their fixes.

A Don · 10-30-2020, 01:54 PM

My hat is off to you!!

Epollan2000 · 10-30-2020, 10:53 PM

Quote:

Originally Posted by Skip426

Thank you for wrapping up you post , with good info on what you found to be your problem.

That has to be a weird one; a problem on a coach manufacturer circuit , with wiring in the ceiling , interfering with the an ECM in the chassis harness.

Could you post your, coach's chassis manufacturer and the Allison trans ECM location .

I like to keep track of the really weird electrical issues and their fixes.

Freightliner chassis. CAT 3126b engine. Transmission ecm is located in engine compartment. Attached to the box surrounding the engine (bed frame).

Skip426 · 10-31-2020, 11:07 AM

Quote:

Originally Posted by Epollan2000

Freightliner chassis. CAT 3126b engine. Transmission ecm is located in engine compartment. Attached to the box surrounding the engine (bed frame).

OK ; thanks again , this sounds like it's exactly the same as mine . Thankfully I've already converted my interior florescent fixtures (12 ) to led.

On more question ,

, do you know your chassis build date ?
There was a major wiring harness change , including dash gauges , in Jan 1999, on the Freightliner assembly line . Some coaches built and sold as 1999 , are actually on a 1998 F/L chassis.
Should be on the chassis info sticker , mine is on the wall , low to the left of the drivers seat.