Bob - 95 993/C2

Bulbs seem okay. All other rear end lights work fine.

Any ideas? Thanks!

kkim

Reverse light switch?

https://rennlist.com/forums/showthre...e+light+switch

TYNUSKT

I don't have the answer but actually have had the same issue for several months on mine as well.

BS911

Here's an idea to test out your reverse switch. This is how I proved my switch to be faulty.

-Remove BOTH reverse bulbs. This puts no amperage load on the switch.
-Using a voltmeter, you should read 12 volts at the bulb socket with the ignition switch on and stick in reverse.
-Insert a bulb in the socket you aren't reading voltage in and see what the volts do... if it drops to 0 when the bulb goes in then you loaded out the switch and it shorted. Time for a new switch.

2ndof2

My '96 has the same problem right now. I just paid a mechanic 2 hrs labor to try to figure it out but I did give him the heads up about the switch possibly being bad even before he got started. At first he didn't think so and then later said he does....He did not have a switch in stock so jury is still out on this. This may just be a strange issue with my car, but when the engine cooling fan goes on the lights don't work. When the fan is not running they work fine. This leads me to believe maybe its the switch but possibly its a grounding issue since both the reverse lights and engine cooling fan apparently share the circuit (or so I am told). Brian, you suggest it may be a short. Wouldn't that just blow a fuse instead? In my case the fuse is fine. I'm not so sure my new mechanic is that proficient with electrical on these later air cooled cars. I hope your mechanic is better if you need one Bob. Definately post what the solution is/was when you find it. Maybe you can check and see if those lights work when the engine is cold, the fan isn't running and you throw it in reverse. I'd be interested to hear if yours does the same thing as mine or not. We'll get this figured out!!!!

Bob - 95 993/C2

I waited until a local p-car place could get it on a lift... it's the switch...easily tested by running a jumper across the two plug in wires at the switch with power on.

So it turns out the switch is one that has been used forever in various porsches...and as others have suggested, it's not all that robust. I looked around some other aftermarket parts places (since it's an established and common part) to see if the 69-75 buck part was available elsewhere but it does not seem to be from my search. I was about to order it from Pelican but after shipping, it's as cheap from my local folks.

Thanks all for the discussion and ideas.

tj90

Thanks for the tip brian. I tried your diagnostic and my switch seems to be bad too!!

stace

I had this same issue and solved it for 5 cents - its easier to take the switch out and test the switch than take out bulbs, etc. its located on the side of the transmission housing (passenger side) and has 2 push-in wire connectors. remove the switch from the transmission housing and clean the internals of the switch. I soaked the switch with some electrical contact cleaner. then I soaked it in some WD-40. exercise the little metal plunger that activates the switch during this process with a small nail or similar tool. now just reinstall the switch. (cheapest price I found for a replacement switch is about $90)

after 6 months my reverse lights still work perfectly!!!!

tj90

Awesome. Ill give it a try. THANKS!

csertich

I know you said all other lights work but I have to ask anyway-do your foglights work? I dealt with the problem of my foglights and backup lights intermittently not working for a couple of years. If the foglights didn't work, neither did the backup lights and vice versa. They are on the same fuse, at least in my '96. I finally figured out that if I pulled the relay closest to the fuse for the fogs and backup lights and put it back in, I could get both lights to work for awhile. I replaced the relay and still had the intermittent problem. Pulled the relay out, spread the 'prongs' on the relay so I could get it to seat better and never had the problem again.
Good luck.

tj90

csertich - my fogs work, but thanks for the tip. im sure that is a nugget that will come in handy at some point.

tj90

stace - your rehab worked perfectly. I cleaned the internals with solvent and shes working like new again. Thanks for the tip.

stace

glad it worked!!!! RL has been a huge help to me. nice to return the favor once in awhile.

Mark Harris

I love this place. While doing my last oil change I pulled this switch cleaned it and put it back in.

Kinda forgot about it, but when backing into a parking spot today I noticed the reflection of my back up lights in the car behind me. Wow! I don't think they ever worked the whole time I have owned my car.

This was a 10 minute DIY during an oil change that like Stace mentioned probably cost me 5 cents in WD-40.