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Porsche 928

Porsche 928 Care and Feeding – Central Electrical Panel Refurb

Probably one reason that the 928 can be had for such reasonable prices is that they may just have a wee bit of a reputation as being a maintenance nightmare.  Ya think?  The car can be intimidating and when things go wrong, making them right again can be a challenge.  Also, since they can be had for very cheap prices, some folks probably don’t want to commit financially to the various maintenance tasks, thus leading to “deferred maintenance”.  My car is basically sound and the previous owner did a lot of good things maintenance wise.  But after having the no start issue that I chronicled here I was a little gunshy about the car’s reliability.  It was time to do something about that.

First I spent a lot of time reading forums such as Rennlist.  I also bought a CD crammed full of shop manuals and tutorials by experts such as Wally P.  I was even fortunate enough to obtain a set of paper shop manuals.  There seemed to be a couple of recurring themes.  Electrical issues and vacuum issues.   Earlier this year I used a tutorial off the Rennlist 928 forum “sticky”  NEW VISITOR? Here are some answers to frequently asked questions.  to tackle the clean up of ground points, most of which are in the engine bay or in the passenger footwell.  I also replaced the ground strap at the battery.  A major task remained, that being cleaning up the Central Electrical Panel, also located in the passenger footwell.  There are several good tutorials on Rennlist regarding this job so I won’t go into too much detail.  And without further suspense, here is what the beast looks like!

DSC00257It is pretty intimidating.  The first step is to disconnect the car’s battery.  There is one thing I want to mention at this point.  The wiring connections along the bottom can and must all be unplugged.  I couldn’t get mine to unplug until I discovered the secret.  In the bottom middle of the panel there is a red release handle.  It’s barely visible above behind the bundle of blue wires. Pull it straight out and it releases the plugs.  There are maps on Rennlist that show what all the relays and fuses are and where they go.  The wiring plugs are colored coded and embossed with A thru Z lettering to keep you from getting them mixed up.  After you pull the wiring plugs and disconnect several +12V leads as well as several ground leads the whole panel comes out and can be laid on your workbench.

+12 volt wiring connections at the top of the panel

+12 volt wiring connections at the top of the panel


Front side of panel

Front side of panel – Its upside down but the “red handle” can be seen at the top.


Back side of panel

Back side of panel

Don’t worry, you don’t have to touch that snake’s nest of wires on the back side of the panel!  I had a simple little plastic fuse puller that you can buy for a few bucks that made short work of pulling the fuses.  I cleaned all the contact surfaces with Deoxit brand contact cleaner.  It is recommended by folks on Rennlist and available from Radio Shack.  I pulled and cleaned all the fuses.  Then I pulled and cleaned all the relays.  Note that a few relay sockets are intentionally empty.  Also one socket for the wiring plugs was empty on my car.  Take lots of photos!


Area behind the panel

Area behind the panel

Don’t forget to clean the +12v connections as you put them back together.  There are also some obvious ground connections that can be cleaned.  Remember, German cars generally use brown wires as color for ground wires.

And that’s it.  Not so bad, in the great scheme of things.  When I was done, the car started right up!  It was probably my imagination but it seemed to stir to life with renewed vigor.



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