Turn signals still kaput

[BLK87S4]

Okay, I'm working on a friend's 85 911. When you turn on the turn signals, the solenoid starts to buzz (the low voltage buzz). I've cleaned each bulb socket. The switch as 12V running to it. The solenoid only has 5V running to it. When you run a jumper to the solenoid, the signals work. Okay, so it's a short or a bad ground connection. Any thoughts as to how I can pinpoint the ground would be appreciated.

Thanks!

[billybek]

Sounds like the switch itself is giving you a voltage drop and when you are bypassing to the solenoid it works correctly. You have 12 volts at the column at the switch or at least going to the indicator switch? Then only 5 volts at the input for the turn signal relay? Something must smell hot when that buzzing is going on! I wouldn't recommend looking for smoke while that is happening.
If the battery is off and you can isolate the wires through the indicator switch see if there is a bunch of resistance through it. If you can isolate the wires to the switch and to the signal relay input see if there is any shorts (no or little resistance) to ground.
Do you have a wiring diagram for exterior lights?

[BLK87S4]

Not really. I have some partials I've downloaded from the web. Another recommendation I have is to install a fuse in each wire and let the blown fuse tell me which wire I need to chase. I have the entire harness exposed and have spent a few days chasing another short to the interior lights. I thought they may be related, but looks like they are not.

Thanks.

[billybek]

See if your friend will spring for the Bentley manual for the later mid year cars. I have the SC series manual and the wiring diagrams are pretty easy to follow.. Mind you I rewire existing control systems for large commercial chillers so it may just be my impression.
A good diagram is worth your while and if your friend is compensating you by buying the beer it may be cheaper!!!
Still sounds to me that if you can get the right voltage into the switch and low voltage out to the signal relay, it must be the indicator switch on the column.
Check the voltage at the left and right lights on the dash. I honestly don't know how difficult that will be but those are the only thing between the column indicator switch and the signal relay on my drawing.

[jrumiano]

I not sure this will solve your problem, but I think it's worth a look.

I had a fast right turn signal on my 85 911. I tracked the problem down to a bad/corroded ground connection behind the reflector on the front turn lamp. Take the lens cover off, and look for the Phillips that holds the reflector on. Behind the reflector there are several spade lug connections that are a likely cause for problems.

Good luck,
John

[billybek]

The switch as 12V running to it. The solenoid only has 5V running to it. When you run a jumper to the solenoid, the signals work.

Would this be the case if the cause was a bad ground? These glitches can be really frustrating to work out. Try to keep it simple and eliminate as much as you can//

[BLK87S4]

I cleaned and removed each of the signal housings. The front was terribly corroded. I've replaced about 3 wires in the harness so far that have melted due to a short. The interior lamp's fuse was blown and it would smoke the solenoid if I let it. I've also found many disconnected wires just "hanging around" but they aren't part of the turn signal system. I'm basically rewiring a few circuts and am about to do so w/the turn signals.

I appreciate everyone's advice....Please keep it coming. I'll post the "ah ha" moment when it happens...

Robert

[HarryD]

When your rewiring the car, do yourself, your mechanic and a future owner of your car a favor and duplicate the factory wiring including the colors. This will help facilitate troubleshooting later on since they and you will only need the factory wiring digram to trace out the circuits.

[billybek]

I guess the "ah ha" moment never came,,,,,