blown 87

A person would think they would have lighting at the shift lever, but the do not unless it has been retrofitted with them.

SteveG

GTS: I replaced the bulbs in the cluster. As before I only have "R" lighted. Could it have anything to do with the cable and alignment at the console? I tightened up some slack underneath at the connection near driver's rear wheel, but the index at the console is still slightly off. I could get another turn on the adjustment back there.

mj1pate

Weird.....I noticed the wiring connector on the back of the ignition switch cylinder and that it was retained by a metal bracket. The bracket didn't have a death grip on the wiring connector, but obviously was there to keep the connector from popping off. I removed the bracket last night and tried to carefully remove the connector off the back of the ignition cylinder. It looked like it would work itself free, but I deferred trying more until today. Well, today, after starting the car and turning on the headlights, I got the old cyclic headlight up-down situation. Hmm....from working the wiring connector loose a bit? It was firmly on when the headlight business was going on today. What are the odds that I excited a marginal ign switch to fail?

Mrmerlin

the odds are pretty good you have a failing Ignition switch

mj1pate

It seems quite possible....Is the electronic portion on the back of the key cylinder normally the only that requires replacing?

underdog928

While you might have a failing ignition switch (bouncing headlight problem?) the PRNDL lights are controlled (aka powered) from the two pole switch on the steering wheel lock shaft that goes between the ignition switch and the steering column. This is NOT the main ignition switch on the back of the key tumbler.

here is a picture of the switch I'm referring to:



For a good writeup on the workings of the PRND32/PRNDL lights look here:

https://rennlist.com/forums/928-forum/455697-transmission-switch-prnd32.html

(NOTE: the above picture is Tony's post #33)

safulop

OK, good, there's not supposed to be any lights down in the center console at all?

I was wondering about this, I thought it was OK for the shifter because of the heads-up display in the instrument cluster, but now it is still kind of hard to see other switches like windows and rear wiper?

-Sean

mj1pate

Thanks Bob; I'll review the link. Is there anything electromechanical in the ignition tumbler itself? Of is all the ignition electromechanical workings in the switch connected to the back of the tumbler cylinder?

Also; I'm having a hard time finding the single pole switch in the picture in the parts catalog. Does anyone have a part number for it?

underdog928

The switch is mechanically operated by the steering wheel locking shaft. I think it's item #28 on PET 403-05, listed as "buzzer contact", which it also does.

Part Number: 911.613.125.00

G Man

I need to replace the neutural switch on my 84'. Did you use the Porsche part or were you able to find a less costly substitute that will work. I know there are Merc parts that will fit.

mj1pate

Bob....when PRNDL lights failed (only after turning on the headlights) I shorted the connector to the single pole switch and this did not affect PRNDL...they still were not illuminated.

Landseer

Have you inspected the reverse side of the CE panel carefully for wires that are partially melted together?
Edit: just saw on another of your threads where stan suggests this too.

When you have melting anywhere, especially when also having arm-bone-connnected-to-legbone electrical problems like your car has, then its wise to start picking through the harnesses and panel for more melting.

underdog928

Do you have power on that switch? Actually, you must, because that's how that circuit gets power with just the ignition switch in position 1. Check it anyway and while your at it, with a voltmeter on it showing 12v, turn the lights on and see if that voltage drops off.

Also, it might not be a bad idea to as Landseer said and check behind your CE panel for shorted wires. This is by no means a trivial exercise, but in your case it might be a good idea. At the very least, you should replace all (yes ALL) of your fuses and clean the contacts on all your relays. Even if it doesn't fix this problem, it will probably fix problems you don't know about yet!

mj1pate

Not a bad idea.....

yes, A cursory look behind the CE panel looked ok...a more detailed investigation is forth coming. All relays and fuses (except the headlight relay) are new.