Last evening was the first time I’ve driven my newly-acquired 2003 996 C4S at night, and I have a strange problem with the turn signals. When the headlights are turned on (or the parking lights for that matter), all 4 turn indicators (front/rear and right/left) illuminate steadily (not flashing) as well as the right and left turn indicators on the tach. While driving that way, when I try the turn signal stalk (on the steering column), the turn signals don’t flash. With the headlights turned on the emergency flashers won’t operate, but they do if the headlights are off. With headlights off, everything functions as it should.
The only thing I’ve done which might be a contributing factor is to wire the side markers into parallel with the turn signal circuits to flash with the turn signals [http://gallery.rennlist.com/gallery/album103].
Has anyone else had this problem? And if so, what was the cause and the solution/fix.
Thanks.

 

Sounds like it's a wiring problem, if everything worked correctly before you did the side marker change, there-in-lye's the problem.
One word of caution if I may: be very careful playing with the electrical systems/wiring on Porsche's because they are temperamental because one circuit can control several things which may not be related at all.

 

Never drove it at night before that wiring change, but I would hazard a guess that if the procedure given in that thread produced a problem, then guys would have posted about that.

 

It sounds like you ran your turn signal wires to the sidemarkers but left the side marker connection still in place. So when you power on your headlights you actually are energizing the circuit for the turn signals.

You should probably disconnect the side markers from their original wiring and leave only the turn signal wiring connected to them.

I plan on doing this with an independent run and using these sockets instead of the factory ones to avoid this issue.

If you want your side markers to serve as marker lights and turn signals you may need to buy a dual filament bulb instead.

http://www.ebay.com/itm/168-194-2825...5bf4c1&vxp=mtr

 

Problem solved. The instructions in that Rennlist thread are indeed correct. I misinterpreted them, and after re-wiring correctly, the side markers will now flash with the turn signals when the headlights are on.

 

Glad you got it resolved. Just saw the instructions. You basically disconnect the ground wire to the side marker and replace that with a splice of the signal wire. I wonder how the marker gets a ground as a result of that? Does the signal blink in synch with the front or does it blink after the front signal? The animated gif that was posted shows it blinking after the front.

 

It's beyond my high school physics study of DC circuitry, but I'm guessing that the side marker gets its ground out through the turn signal circuit - as the side marker and turn signal alternate their blinks.