Rear taillights don't work unless brake Pedal is pressed, otherwise no rear lights!!

[GTODually]

Got pulled over on my maiden voyage home with the dually, I got pulled over for no rear lights. I checked before I left but realized that was just with my foot on the brakes and someone checking. Any ideas? The truck has some ghetto rigged areas I keep finding so not sure if its another one or a simple fix. Any ideas?

 

[SlinkE]

Same thing happened on my 90'..it was a bad ground on the trailer wiring harness. .easy fix..
I've found that with any electrical gremlins it's good practice to check all your ground connections. .even those seemingly unrelated to the problem area...before proceeding to other more complicated(expensive) troubleshooting. .a volt metre and my time has saved me plenty of dough..
This may not be your issue but its somewhere to start..

 

[BadBowtie 98]

Ground issue... Just like Slinke said Trailer Wiring harness

 

[GTODually]

Where would I locate this ground at? I could build an engine with my eyes closed but I'm clueless with electrical issues

 

[SlinkE]

If it's youbTrailer harness justbtrace back from the trailer connector and find the wire that attaches to the truck frame..Usually green, sometimes black..if its a ground issue somewhere else, break out youre multimeter and start checking.

 

[poncho62]

I see nothing about trailers in the original question......

Your bulbs in the rear lights of your truck has 2 filaments, one for brake/signal lights and the other for your running lights. If the brake lights are working, its not likely a ground. There is a fuse for your running lights, check that 1st...If its OK, you must have a break in a wire somewhere. Start at the bulb with a tester and work your way forward.

 

[SlinkE]

You're right..my experience with the exact same issue, and the method used to solve it, have no place here..go fix your bulbs..it couldn't possibly be a ground issue..

It's been a couple years since I contributed to forums such as this .. for exactly this reason..loud mouths like poncho, who can't accept the value of anothers input..

smell ya later

 

[poncho62]

Not a matter of accepting your input, Zippy.....but he is asking about his truck tail lights, not trailer lights. It may be a short in the trailer harness, but you do the basics first......Sorry your feelings got hurt by MY opinion

 

[SlinkE]

2

....Sorry your feelings got hurt by MY opinion

yeah..that'll be the day . You're an idiot. .

A trailer harness always pigtailed off your taillights. .and when the ground connection there gets fouled, wonky things happen. .you're right to start with the basics..that is the most basic. clean the connection and re-attach.

keep on truckin.........Zippy.........

 

[Horns]

Might have already been said, but if they're really really dim, check the ground wire.

~Via Mobile