Porsche Repair: 85 Porche 944 Electrical problem, porche 944, porsche engineers

Question
Hi, I have a 85 Porche 944. It was running fine. I parked it, went to restart it and it would not start. The power windows, coils, acc. switches, and headlights will not work. The dash, fog, and parking lights, moon roof, radio, and starter will work. I assured it had a good ground to the battery. There are no visible fuses blown, or wires melted.    What else can I check to solve the problem and make it run again?  Thanks, John

Answer
Hi John,

It's taken awhile to respond because I've been studying the wiring diagram for your car and I am quite perplexed.  It's quite complicated and involved and obviously something the Porsche engineers want to keep secret.

Anyway, there seems to be no relationship between the components that are working vs those that are not.  For example, "all working are part of the hot at all times components".  This commonality does not exist anywhere with the items you mentonn.

There are two areas you might consider, given the abrupt nature this problem arose.  

One, the 944 has many "junctions"...meaning little blocks mounted to the body or chassis where groups of wires are brought together and joined under one screw.  From there the wires are re-distributed to other areas.  These junctions are always ripe for corrosion and loosening of the srcews.  It's quite a tedious job, but at this point I can't driect you any more specifically,

Two, there are many relays as you know,  Two are quite puzzling.  One is called Relay X and one is called the "Control" relay.  In the past these have caused others problems.  Find these and test them.  If you need info on an easy way to test them at home, write back.

I wish I had more to offer at this point.  Good luck.

Dave