Bjbpe

This has to be the simplest question that has ever come across this board but, after owning a 928 for twenty-five years, I have found out that nothing with this car is simple.

The question: The dimmer switch under the pod which is supposed to raise and lower the light intensity in the various dashboard instruments is no longer functioning. Should I replace the switch or should I change oil? I know this sounds ridiculous but this car is pretty complicated and I don't really want to buy a switch at $75.00 if the car really needs a new (you name it for anything but a dimmer swictch).

Thanks all.

destructo_low

I imagine the switch is as simple as a slider on an exposed wiper contact. You could probably try cleaning the wiper and slider. You could always buy a two dollar potentiometer to wire up instead of an OEM switch.

*edit - You can try to clean it, but it may be harder cleaning that spring off. Have you checked to see if any solder joints were broken?

Bjbpe

I think I'll pull it out this weekend and do a continuity check. The various 928 suppliers are fair and helpful but they have to make a profit to stay in businesss.

I made the crazy comment about adding the quart of oil only to exemplify how strange some of these secondary effects can be.

Rod Underwood

Pull the two contacts off and put a fuse into them and see if the lights work. If so, then it's the switch, if not, it's something else. They are spade connectors and a fuse fits perfectly.

Good luck
Rod

destructo_low

Absolutely. You can always fix one part of the car, and then, something entirely unrelated stops working.

F18Rep

Yep, thats what I did - actually no fuse just a simple jumper wire. Its a hack but ya gotta have priorities and besides all my pcars are always at max brightness anyway (which is not that bright)....Bruce

Bjbpe

Great looking dog, Bruce

MainePorsche

There's one screw holding it in place that does not have to be completely removed, in order to remove the rheostat. I would take it out and give it a good cleaning. When I did this, I did get better performance of the rheostat's function.

LT Texan

this.

bypass it. forget it.

jeff spahn

You could put LED's in the POD and forget about the dimmer necessity. It will be bright. Here's a link to the site to tell you how to do it.
http://www.ed.scherer.name/Porsche_9...0to%20LEDs.pdf

Bjbpe

Hey Jeff (or Batman or Robin)

I couldnt get the address to work. Could you check it,please?

Thanks.

Barney

Ed Scherer

Give it plenty of time (like a minute or two)... it's a PDF file hosted on a server with a really slow Internet connection.

Jchiodi

Just to resurrect this thread..... I'm going to pull and jump the wires on the dimmer. Looking up (with great difficulty, glasses falling off, back bent), it looks as though there are two white connectors on this thing?
The wires look different for each though.

One has a black/blue two wire into it? the other just black, I think?

I know that the dash lighting works, once when my right headlight was out, it worked until I replaced it!

The other time, just out of the blue it worked! I was so happy I just had to turn the car off and restart to see it again. Hasn't worked since. Think I will change the oil

Ed Scherer

Yup, BK and BK/BL wires using 6.3 mm blade connectors; they should just pull off (but might require a little effort).

Before bypassing it, you might first try just cleaning it and then applying some some contact cleaner (DeoxIT would be good, if you have any). Important: when applying contact cleaner, don't just do the wiper and resistance coil, also do the other end of the copper wiper where it first contacts a wave/spring washer and then the brass contact (get contact cleaner on all of that stuff); this is all part of the circuit. I actually found that even with a brand new part, it didn't work reliably until I used contact cleaner on that center area. You can probably do a better job on this with the rheostat removed from the car.

You can also try to compress the tubular rivet (that passes through the center of the adjustment wheel) by hitting one side of it with a punch or small hammer, with the other side on an appropriate hard surface. Just make sure not to overdo it or damage the fragile parts (e.g., by hitting the plastic or not being careful about what all is contacting the hard surface on the side you're not striking).

Of course, you can replace it, too; these are still available (but not cheap; a new 928.613.121.01 goes for $64 at 928 International).

(Note: there's a similar thread to this one—Dashboard lights dimmer—that also includes information on the '90+ rheostat).

On your '86 (and through '89), the rheostat will look like this (but I'll bet it's not as nice and shiny ):


(large version)


(large version)


(large version)

Jchiodi

I have no doubt that it doesn't quite look like the one above . My lights, when they did briefly shine were so dim that I can't see me ever dimming them!

Back to on my back. And thanks for the detail in your post. Every time I look into this beast I find something else to spend money on. Waiting on a new shifter, and new upgraded chips! Just tightened up go pedal, and I can tell the difference just doing that

The fun never ends!

jc