Electrical

I have a issue that shows up after I drive my 1989, 928 S4 on a warm day (65 F +) , that after I shut off my car, a code flashes on my dash, TYP04-6, that will continue to flash until I reset (disconect the battery) and the car cools down. When the code appears , loose my fuel gage reading.  I have driven the car on cool days without the code ever showing, and driven on hot days were the code will not clear after 8 hours of the  battery disconected.  The car will run fine with the code showing, as it does not seem to affect performance.

The lesson  learned is to never throw anything out.

Here's the question, I was tidying up the engine bay and found a short rubber hose with a light bulb inside that was hooked up to the alternator exciter (blue wire, pin 13, or 14) in the connector at front passenger side near the engine lift bracket.

I believe this was added by the previous owner (over 20 years ago) and assumed it was for diagnostics or something.

Seemed innocuous enough to remove and tidy up the connection. Also misplaced the hose/bulb apparatus.

I have no Back-up lights on my Porsche 928, I have checked the lights, & Relay Both Good, I have clean the Battery connections, This is a summer car only, Just when for an inspection, it failed because of no back up lights, I ordered & replaced the switch on the back of the 5 speed transmission, Still Nothing, Does that Pin have to be in a special place?, does the manual transmission have to be in a certain gear?, Does the car have to be running when turning the top of the back-upswitch, I am just jacking the car up , not on a lift or all four tire off the ground, I have looked ever

Does anyone know where I could purchase an original AM / FM radio for my 1982 928. I assume that a Blaupunkt was the original. The current AM / FM cassette, a Nakamichi,  is not working correctly and looks wrong. If there are any refurbished units that would be better. My car has speakers in front and back which I need to replace too, but I don't want to cut any holes to keep it right. Any help would be appreciated.

I have searched around on various forums but not found an answer for this starting question. When the car is cold, or been sitting for awhile, it will not start in PARK. The dash will light up but no turning over. I then move the auto gearshift to Nuetral and it will start up without any problem. After driving awhile and everythings warmed up, it will start fine in PARK. In warm or hot weather, it will start in PARK without an issue. I assume its some electral issue in the shift mechanism where it goes into the tunnel. I have not checked relays or fuses.

The rear wiper does not work at all...I have replaced the relay with a new one from Porsch...still not working... could the motor be shot or do you think it is simply not getting power to it ?  Thanks 

Model: 928, Year:1984, Mileage:35000, Type of use:Street use only
I have a 1984 928S that appears to have developed a random electrical issue. Sometimes when I start the car, the windows and sunroof will not work and the brake light indicator stays on. All of the other electrical works and it will drive. Usually I can get the windows, etc. to engage after turning the car on and off a few times then everything works when I drive. Is this a grounding issue, ignition, tail light or something with the brake system? Thanks

Model: 928GT, Year:1991, Mileage:22,000, Type of use:Street use only
I upgraded the head unit in my 91 GT to a modern Blaupunkt my installer recomended bypassing the factory old Amp which we did, however, the Bass sounds awefull with noise it seems to come from the large speakers in the rear( 6.5" I beleive), i have read previously that these speakers are 2 Ohms so they will need to be upgraded to 4 Ohms speakers, my question is , are all the other speakers 2 Ohms and do I need to upgrade them as well? thanks.

Model: 928 S4, Year:1989, Mileage:125500, Type of use:Street use only

Model: 928 S4, Year:1987, Mileage:98,000, Type of use:Street use only
Good morning: Just bought a 1987 928 S4 manual with about 98,000 miles on the clock. The car is in fantastic condition - the only issue we have come up with is the electrical drain which has been alluded to in a number of questions to TechQA. The power drain issue seems to be a well travelled road by 928 owners.Based on your experience, could you advise which components/systems are the more likely to cause the power drain. Any suggestions / tips are welcome. Thanks.