75' 911 signal, parking light electrical problem

randytrish · 09-26-2006, 03:49 PM

Hello all,
I am having a problem with my right front parking light/turn signal. I can't get them to burn. Just recently purchased the car and they weren't working and disassembled and I'm not sure if I'm connecting it properly. I am going by the left side connections, by the way the left side is working. Let me explain what I have.
I have a Grey/red stripe wire that when the lights are on has 12v this is in a wire harness, I have it connected to the top terminal on my light housing.
It has a pigtail that is connected to the top terminal coming out of the car and a black/white stripe to the bottom connector of the light housing. there is a brown wire with a one inch white pigtail connected to the bottom terminal coming from the car. It is not connected to anything else. The odd thing is I have 12v on the wires and can touch them to a ground and nothing happens.
Have I lost a ground somewhere that is keeping this circuit from working? I also have 12v to the small side marker light and it is also not working. I don't have a wiring diagram and probably couldn't read it if I did.
Thanks in advance,
Randy

304065 · 05:14 PM

Randy,

Here's a link to a wiring diagram, it didn't change all that much by '75. There's probably a more accurate one out there for a '75 and certainly one in the factory shop manual. But now you have one, so you can see if it makes sense. People think they are hard to read but they are really easy if you go one step at a time. Wiring Diagram

The other thing that makes it easy is that The Germans, being Germans after all, wouldn't just have the colors of a car's wires be whatever-you-please. No, there has to be a SYSTEM, and that system happens to be called DIN 72552. And DIN 72552 says that a wire terminal labeled "49" is "flasher unit in" and a wire called "58" is "license plate lights" but we really know that it's the parking lamp.

So, looking at the diagram, we can see that the brown wire (in German cars, the brown wire is usally the ground wire, that's that pesky DIN 72552 again) connects to the turn signal housing, and that one terminal of each bulb is connected to the housing too. That's where each bulb gets its ground. So now we have to figure out which wire connects to the other terminal.

Well, looking at the diagram, you can see that the parking lamp or "58" wire, which is the gray with red stripe, is connected to the forward-most bulb in the housing. This is the forward parking light. You can see also that the small white wire is connected between the same terminal that the gray/red connects to, and runs to the rear-most bulb in the housing, this is the side parking light. The front and side parking lights come on together, that's why they are connected with the white wire. Finally, the turn signal or "49" wire, which is the black wire with white stripe, is connected to the center bulb in the housing.

Does that help? I told you it was easy.

randytrish · 09-27-2006, 04:22 AM

John,
Thank you so much for your help. One problem, it still doesn't work. Here's what I have and please bear with me. My brown wire (ground) is hooked to the lower terminal coming from the car. I see no place on the housing to attach it for a ground. The left side that is working has this pigtailed wire connected to the bottom connector and laying loose in the housing cavity. One thing that I'm seeing different (besides one works and one don't) is that when I hook up the power lead to the light housing, I have 12v across the bulb. I have tried to run a jumper and ground the housing, nothing seems to work.
I really appreciate your patience.
Thanks, Randy