Minor electrical issue

I'm about finished putting an AAR back together that was painted and of course, had the usual fresh paint and bad grounds... I've got everything working as it should be, but there is one annoying gremlin that I can't figure out.


When I step on the brake pedal, the dash mounted reverse light illuminates (factory 4-spd car). The light works as it should when in reverse. There are no cuts in the dash harness, nor the taillight harnesses that I can see. Where might be a good spot to check?
TIA

Ground strap between column mounting stud and mounting bolt that holds the bracket the nylon square washers are captured in. Ground between firewall and back of cylinder head.

when you are in reverse & the reverse light is on, is the white wire at the brake pedal switch hot? Foot not on the brake pedal.

I would make sure the tail light housing is grounding to the body. Might be trying to ground through the reverse light?

Otherwise, the wiring may not be correct?

Take the reverse light bulbs out n see what happens.

For the proper method to troubleshoot grounds, go here:

https://www.hemmings.com/magazine/mus/2015/11/Ask-Ray---letters-from-November-2015/3749137.html

Note that the circuit has to be activated or powered during the test.

I have the same problem..where is the ground located at the tail lights and does anyone have a photo?

in general the bulb metal side contacts the socket which is grounded to the housing which is likely grounded to the body thru the mounting screws which I ain't telling you anything you don't already know & if you take a jumper with an alligator clip on one end & clip it to a KNOWN good nearby ground then stick the thin pointer on the other end into the side of the bulb area to contact the bulb metal side that will elim or confirm a ground issue on that side of the vehicle.

Thanks for the suggestions, but those nylon squares and the ground strap aren't used on the E-bodies.

Your '70 cuda too Roger?

I'll get on it tomorrow Robert.

Thanks for all of the suggestions guys.

Yes I do James ..A slight glow when the brake pedal is applied..Very frustrating ....

(Stake the pedal and follow the reverse circuit back...

Well, ran a jumper from the driver's side taillight to the left side marker. Worked like a charm. I know that early built '70 'Cudas used an extra jumper, not sure why they did away with it.

This is the factory jumper on a '70 'Cuda survivor with a B05 SPD. Not sure when it was phased out? I thinking on this AAR I'm working on, that the new paint is screwing with the ground.

(EVERY ground I have is to fresh, paint-free steel...

With a swab of di-electric fer good measure...


20+ years of zero issues...