Porsche Repair: 1983 Porsche 928S, porsche 928s, negative battery

Question
Dave, I have an 83 928S that was suppose to stay in Germany but was imported. I bought the car about 7 months ago and recently most of its auxillary components stopped worked after a period of intermintant problems. Within the past month my radio reception has gone bad, heater fan stopped working, windsheild wipper squirters quit. My drivers side window now only somtimes works and also my driver side tailight was out which looked like it had overheated and cracked the glass. Upon replacing, it is working fine. Also my speedometer and odometer stopped working recently. Any thoughts? Thanks  

Answer
Bradley, you are having quite a bout with the elctrical gremlins!!!  I suspect the first four items are not related to the taillight and neither is related to the speedo.  Working backwards, I can't even guess wwhy the speedo stopped working, but the burned oiut taillight sounds like there is a hot wire leading to it that has a bare spot...and the bare spot can sometimes touch metal.  When it does, the circuit is completed but not protected by a fuse, so te light will shine for awhile and then burn out.

As far as the first four items, I'd look to verify that each one is grounded properly.  Sometimes, like the radio, there will be a ground wire.  It needs to be checked to verify it is secure and is actually touching a piece of metal that eventually is traceable back to and is connected to the negative battery terminal.  For other components, the "friction" of being bolted to a metal panel is the means to be grounded...but as above, the connections need to be checked to ensure the component is reallly touching the metal panel (not rust) and the metal panel can be traced back to a connection to that same negative battery terminal.

This process will take quite a bit of you patience.  Prepare your mind well.

Dave