car is an 86 s4 n/a. ive had problems with my running lights before, only now im completely stumped. before the wiring harness behind the switch burned out...so i replaced the wires and the light switch and its worked flawlessly, until about 4 months later the running lights stopped lighting up. the harness and switch are fine...bulbs are good, fuses in working order... so any ideas would be extremely helpful... i would like to fix this asap...i will provide any more info if needed

 

you might want to check the pins inside the plug. See if they are not bent or missing any. Just a suggestion good luck.

 

How can you tell the switch is fine?

The switches fail internally due to a poor solder joint near the connector (that also takes out the White/Green wire) and oxidation on the switch contacts in the **** portion.

 

With good fuses........................pull the plug off the headlight switch. Then jumper a wire b/t the W/G wire and the R/B wire in the plug. The front and rear running lights should light up proving the problem lies in the switch. The W/G and R/B are located next to each other in the plug. See wiring diagrams.

 

im assuming its good... louis(RRR) brother hooked it up with the switch but i could be wrong....ill have to try hailers suggestion when i have the time.......o i forgot to mention.....even though the running lights fail to light up...the dashboard lights still work....before both didnt light up till after i replaced the switch and harness

 

Well that confirms the fuse is good and at least part of the switch is working.