rear running lights

[rednckii]

Ok so i have been searching all over and still have no luck. My rear taillights are not coming on at all on my 66 m35a2. I have brake lights and turn signals but not running lights. Have new wiring harness front and rear new 3way switch and new turn signal switch. Still no running lights have checked the grouns an it is good could there be any other culprits im missing. Bulbs are good even tried switching out lights with led set i had still nothing. Could a bad brake switch cause this any help be great im losing my hair over this keep pullin it out.

 

[steelandcanvas]

The brake switch won't be the culprit. If you have brake, and turn signals, doesn't sound like a ground problem either. Take a look at the tail light sockets, any corrosion? Maybe take a meter and check for voltage at wire "E" (wire #21) at the trailer receptacle. Having voltage there would indicate a problem with the light fixtures themselves. No power there would indicate trouble upstream, or toward the front of the truck. I've included a schematic for your troubleshooting pleasure. Good luck! Let us know your progress.

 

[Darwin T]

when i put on my right front led turn signal it did the same thing. everything worked but one thing. the plug was loose. my mechanic fixed it. he undid the plugs and slid back the rubber plackard and pushed in the pin in on the one giving me the problem and it worked fine. pushed the rubber plackard together and taped it. i have had no problems since. i also had a new wiring harness front to back. i also tried several lights also.

 

[cranetruck]

On the rear light housings, make sure both mounting screws are grounded, in particular if they are made of plastic. The grounds are separated inside.

 

[M813A1]

Check the 3 leer switch !! you could have a bad 3 lever switch !!

 

[rednckii]

Thanks for all the info soon as i can i will check the plug connections first and ensure they are all properly seated. After that i will check the power at rear trailer socket todays family day so have to see if can sneak out for a minute. Ill let yall know what i come up with thanks.

 

[rednckii]

Alright i snuck out and checked a few things all the plugs are in securely still no lights. I checked for power at the plug receptacles no power at 21 but showing pwer at 24. This is at the plugs at the light. Any suggestions does his man have a crossed wire being that 24 is for the blackouts. I have switched over to a N.O.S switch and still same problem think i should take apart and redo the connections where the wiring haress oes together.

 

[srodocker]

are all the bulbs good i think theres 3 bulbs in the bucket. mine did the same thing but i had a bad ground. i would follow wires. yea it sucks but best thing you can do at this point

 

[rednckii]

finally got a break from training and the holidays after runnin the truck at night i noticed the blackout lights were on in the rear. Went out this morning and switche wires 21 and 24 around now i have all working lights and everythig working good. Not sure if harness is crossed somewhere or if it is in the lights themselves either way just happy there working now. Thanks for all the help just surprised it was the wires crossed.

 

[Darwin T]

glad you get it working.