vsalvato

I am looking for a techncial hint as I am a fresh new Italian owner of a Porsche 928S4 (MY88, AT) which I bought from a German dealer; besides some other minor electrical problems which I got my mechanic to fix I have one which is giving us some headache; the backup lights do not work and the reverse gear indicator light on the dashboard does not light up if the stick is set on reverse. All the other indicators for the other gears work... very strange! The mechanic said that taking the connector apart from the switch he is able to bridge the cotacts and light up both the back lights and the dashboard indicator light but something must be wrong with the switch.

Following the hint from a previous post on Rennlist he also took apart the connectors in the spare wheel compartment, cleaned them up and re-assembled without success. Is the switch in your opinion the only component to replace, in case? Is there any other component inside the gearbox which might be responsible for the problem? I truly hope that I do not need to open the gearbox to fix it... thanks for your help, in any case

SharkSkin

Sounds like it's just the switch. Easy fix.

WallyP

Before getting involved with the switch, check at the connector in the spare tire well. Use an Ohmmeter or multimeter on the resistance setting to check for continuity in Reverse (less than five Ohms) on the connectors between the gray/yellow wire and the black/yellow/red wire. Should be open (no continuity, infinite Ohms) when not in Reverse, closed (less than five Ohms) when in Reverse. That will condemn or validate the switch.

vsalvato

Tks indeed for the quick response...
Wally, I insisted with my mechanic asking him to double check the connector in the spare tire compartment but he said they were OK and even though he cleaned them thoroughly; he also stated that if by "bridging" the connector he is able to switch the lights on (and when he does so also the light on the dashboard comesup regularly...) this means that something is wrong with the switch itself, either some dirt, lack of contact (he is considering to dismantle the switch and check it prior to replace the part) or something which definitely requires replacing the part; I have id the part# as 000 546 6606; this seems to be the switch itself but is there a complete part sold including the shaft etc.?
Is there any critical part other than this switch (say internally to the gearbox for example...) which might require much complex repair, in case? Sharkskin, you stated "easy fix" and I hope you're right... How long is the replacement of the switch going to require to an experienced mechanic? My mechanic has worked on a few porsche's already but admittedly he is not an expert of 928's.

SharkSkin

Wally, it sounds like the above is pretty conclusive. All connections have been verified with the above test IMHO.

SharkSkin

On a 5 speed it's 5 minutes work once the car is jacked up. Looks a bit more complex on the AT, but not too bad. It's connected to the linkage, if there were a problem with the linkage you would have trouble shifting. Not having done the job myself, I'm going to guess at maybe 1/2 hour's effort tops.

BTW, there is a thread on the subject here. You should be able to get the part for at most $80-$90.

vsalvato

Tks Dave... I went thtough the other post and could not find any additional hint. In my case the only gauge not working on the instrument panel is he R, whilst all the others are OK. Assuming I need to replace the switch can you just confirm if the spare part is just one # for the entire switch and its components? As said I have id the part# as 000 546 6606 but I am not sur eif this is jsut one of the needed components. Admittedly Porsche Spare Parts center should be able to manage when they will be asked but I am getting curious... it may be that they do not have such old parts off hands and if I need to shop on the web I would like to buy all what is needed at once. Tks, rgds

IcemanG17

One thing I noticed when my 88 928 blew the fuse that controls the interior lights was that the reverse lights also didn't work, however this was not noted on the chart....

So do your interior lights (the dome-door-hatch) work? If they don't thats an easy fix

SharkSkin

Looks like it's self-contained, and should be all you need. If any of the linkage needed replacing(unlikely) the mechanic ought to have said something.

vsalvato

Jee... IcemanG17... you hit me with your point; the car had an issue with interior lights when I saw it and tested first time in Germany; It was stated by the dealer that they fixed this bur I cannot remember if the interior lights work or not (and it might be that they don't work any more...) and I will check this immediately n Monday., in which case I will aim to the fuse! Tks indeed...

Mrmerlin

since your checking the interior lights remove all of then with the battery disconnected, and verify that they are all wired the same way

SharkSkin

The portion of the OP that I quoted in post #5 indicates that the fuse was good, at least when the mechanic checked it.

vsalvato

What do you mean exactly>>>??? I am not a proficient electrician...

vsalvato

I will check again interior lights (the dome-door-hatch) tomorrow and I would not be surprised is fosething is wrong with some of them. One thing I do not understand is if the fuse is shared between the interior lights and the reverse lights; I also do not understand (as said I am not a profiecient electrician...) if by "bridging" the connector and managing by this to lighten up the reverse lights and the R gauge on the instrument panel (as the mechanic claims he did) one by-passes the burnt fuse... I doubt this

Lionel S4 - 88

Hello

Am also a fresh new frecnh owner of a