callouie

OK, so I had a rock go through the lens on one of my S4's driving/fog light combos. I ordered a used housing, which is in GREAT condition (thanks 928 Int'l) and rather than replace the whole unit, I just pulled off the wires, and installed the new lens/reflector assembly. Turn it on and...the new lights are both coming on dimly, but the one that should be turning on is slightly brighter than the one that shouldn't be. I unseated/reseated the connector behind the lights, no joy. The 'old' ones are still working as they should.

Any ideas?

Thanks!

Edit: Just put the bulbs from the broken housing in, though the ones in the used housing I bought looked new. Same problem.

dr bob

Check your ground connections to the two housings at the outer end, and the car frame at the other. The two housings are connected together OK, but you've lost the frame end. You can verify this with a meter, after you've disconnected the wires from the lamp housing. Your goal is zero or close to zero ohms to chassis ground, from each of the ground wires that attach to the reflector.

callouie

Thanks! I'll break out the DVM and start checking grounds.

callouie

Bingo. Checked fine. Then not so good. Chased the wire, looks like it goes to a ring terminal with the other grounds from aux lights to one of the bolts holding down some module at the front of the engine bay. Snugged that down, worked like a charm.

Thanks Bob!

dr bob

Hey, glad you found it so quick! Those ground points are on the annual maintenance list for just this reason. Pull the bolt, clean each "layer" of ring terminals until shiny, then reassemble. You can coat the assembled terminations with a little Vaseline to keel moisture and air from causing new corrosion too.