Need help...Tailight ok, brake light not working (bulb is ok)

[bigchillcar]

Hey folks,

My driver side tailight is working properly, but the brake light on that side isn't working. I've tested two working bulbs and that isn't the problem... Any thoughts on where to start troubleshooting?

Oh, btw, my license plate lights seem to have recently quit on both sides recently. I haven't tested the bulbs, but am inclined to think the problem lies elsewhere in this case as they seem to have quit at the same time.

Cheers!

Ryan

[ChrisV]

Start with checking to see if power is getting to that socket. If the running light is working, but the brake isn't , then you most likely need to check the wiring from the fuse. After that, check the grounds. Earlier cars are notorious for having corroded ground lugs, especially around the taillight support structure behind the housings.

The license plate lights are most likely the same thing. But first, check to make sure they are still getting power.

In both cases, a multimeter will work fine, but the car is eearly enough that it can't be hurt by a simple test light (test lights are a real problem with computer controlled systems that are affected by total resistance in the circuit... the early 911 does not have such a system, especially for lighting).

Roll the fuses (that style fuse is also notorious for corroding on the tips, and rolling them often solves issues until you can get them out and clean them properly). Then check to make sure thap power is getting out of them. Since your taillights work, power should be heading to the markers and license lights. But make sure, first. Then again, go to grounds.

[bigchillcar]

Chris,

Thanks for the great tips! For what it's worth, It hadn't occured to me that test lights could cause such trouble in later year cars. I did report in an earlier thread about finding a pair of broken wires (yellow with red stripe) inside a black cover that was hanging down after my car had been in the body shop. They pulled out that left rear tailight assembly to work on the left rear quarter panel. I think that's when my trouble began with the license plate lights as well, supporting your theory of a broken wire somewhere in the chain.

Ryan