chart928s4

After dismantling and replacing a PO aftermarket stereo on my '91 S4 auto I found some orphan wiring. I have questions that hopefully someone here can answer. I'll be doing more diagnosis tomorrow, but if anyone has run into these issue that would save some time.

First , I think the left wire is black/yellow, meaning it should connect to the cigar lighter. But it could be black/green that suggests it should be attached to the rear defogger switch. I pulled the ashtray and lighter out and there is one wire connected to the barrel of the lighter.

Second, where does the bulb go? According to the wiring diagram this is associated with the lighter. There is a 2-tab sheet metal arrangement on the lighter that looks like it's supposed to hold something - is that where this fits? Also, is it connected with the dashboard lighting so it could be used as the "illumination" signal for a new stereo head unit?

Third, i can't find any reference to a brown/yellow wire in the wiring diagrams. Where does this connect?

If anyone has photos of a properly wired lighter that would probably be helpful. Thanks!

Mrmerlin

please post a picture of the back of your ashtray ,
do you have clock installed does it have a lamp in it?

MainePorsche

You should have a Black/Blue for bulb current and a small Brown for ground to bulb. A larger Black/Yellow for current to lighter element and a larger Brown for ground to lighter element. I don't know what that 2 prong brown/yellow is.

chart928s4

Thanks for the quick response guys. Sorry to not give enough detail. This may be a little more involved than I first thought.

My car has an analog clock and rear air conditioning. The a/c has a leak so I dont use it. It is an upcoming project.

Here are photos of the back of the ashtray and the disconnected wires and bulb, alomg with the console for reference. I actually found an additional loose 2 pin female connector (3) after removing the ashtray.

Seems clear that the black/yellow (1) is the lighter power and plugs into the back (dotted line).

The bulb (B) doesn't light and the socket doesn't seem to get power under any headlight setting.

No obvious place for the brown/yellow (2) or 2 pin connector (3) to plug into.

The clock may have a lamp but it seems not to light either. Because:

Fuse 9 was blown and a replacement blew right away when I turned on the headlights. The pod lighting doesn't respond to the brightness ****. It is possible I shorted out something when I placed the head unit. It's also possible I got the car this way and just didn't notice.

My first 928 electrical problem. I assume there is no easy answer and i need to poke around with a multimeter. Also I still don't know where the disconnects go. Any advice?

Mrmerlin

Thick black/Y wire to center of the lighter.
Thick brown to the lighter frame.

Plastic bulb holder to the clock, it will melt in the lighter.
NOTE the lighter bulb socket holder is made of metal.

The black 2 wire connector may go to the underside of the ignition locking barrel,
look under the pod for this this senses the key in the lock.

The Potentiometer for the dimmer should be checked.
or bypass the part and join the wires that will restore dash lights.

check wire diagrams for the brown/y wire

chart928s4

Thanks MrMerlin. Will check those items. Much appreciated.