Gregg K

All of a sudden one night I turned on my headlights, and the instrument panel went dark. That's how it works now all of the time.

I've searched the forum, and I found one thread that describes a connector. I don't have a connector where they did. Another thread talks about a relay, but the thread ended without any more info.

I'm lost on this, and curious if anyone has a clue what could be wrong.

It's an 89.

MainePorsche

Sounds like a bad head light switch. The is a light in the switch which is tied in to the remainder of your dash and console illumination. Sounds like it is shorting when you rotate the switch to turn on.

Gregg K

You may have something there. I notice that the instrument lights go out immediately as the switch is turned. It doesn't wait for the headlights to come completely up.

I'd like to hear more before I start tearing into things. In fact I wonder just how difficult it is to get to that switch.

MainePorsche

Pod switch, dash lights, and center console illumination is via the Black/Blue system. This is the color of the wires through which all of these are illuminated. Two Black/Blues emanate from the dimmer rheostat to feed your bulbs.
Could simply be your bulb contacts in your headlight switch move, and contact, when you rotate the switch. It could also be a faulty/loose contact on the switch as well.

AnatolyL

Speaking of the headlight switch, I also have an interesting fault. When I got my '83 US model (in 2006), and when driving at dusk, when I switched on the headlights there was a sensation in the vehicle as if the emergency brake had been engaged for a split second - a huge jolt throughout the car - but only for a second, and the lights came on, and the vehicle ran normally. Eventually I pulled the headlight relay (a very large double relay in the fuse panel, lovingly referred to here as the CE panel, or Central Electronics panel), sprayed it with electrical contact cleaner, and blew it dry with compressed air, re-installed it, and the jolt was eliminated. This is a $150 relay, so I was not inclined to replace it immediately. Being a member of AARP, I don't find myself driving the 928 much after dark, but I have noticed over time that when the light switch is turned on during highway driving (or city driving for that matter), the cruise control immediately cuts out. This is not intermittent, it is 100% of the time. This is on a car with no other electrical problems, clean grounds, battery ground strap replaced with OEM, etc. Anyone else dealt with, or solved this particular problem?

Ben
83 US model

Gregg K

I seem to be the only one in this situation. After searching, I'm not seeing any threads on removal of that switch.

Can you illuminate me on where this project begins? I take it this is pod removal in order to get access.

MainePorsche

Gregg,
No, no.
It really is simple. All you need is a needle nose plier.
Pull the rubber dial straight off - don't worry.
You'll then see two tabs, at 12 and 6 o'clock - squeeze them together a bit and she pulls out straight. The white cylindrical wire harness on the rear (or front depending on your semantics) will separate from the black end with a little force applied.

AnatolyL

No, the switch removal begins with the removal of the "button". I'm calling it a button because this is what you push/pull/turn when activating any of the 6 switches on the pod. This is a press fit and simply pulls off. Grasp it firmly and pull towards you while sitting in the drivers seat. Unless someone applied super glue or some other adhesive it should come off relatively easily. Once the "button" is removed you will see the switch with 2 retaining tabs on either side. Depress the tabs using a small flat blade screwdriver while again pulling towards you. This should allow the switch to be released from the pod. You will then be able to separate it from the electrical connector. The "button" connects using a "keyed" male/female assembly that only goes on one way, so make sure you see this and re-install it correctly. The same goes for the switch/electrical connector. Look at both carefully to insure proper installation. It will fit tightly... electrical contact spray will help mating the two together and will help prevent corrosion. Call me tomorrow if you need more of an explanation.

Ben
954-614-5689

Gregg K

That was unexpectedly trivial. Thank you.

I want to test this thing before plunking out cash for a new one. I have no idea what these dozen or so connector tabs should do. Is there any information on how to test it? I could start ohming them, but I don't know what to look for. And thanks again for indulging me.

j.kenzie@sbcglobal.net

Used headlight switch $30 at 928 International.

Gregg K

Thanks. I was wondering what their price might be. But I'm interested in confirming that it's the switch before running off to 928intl. Although without knowing the pinout I could spend more time than the 30 bucks. Hell, I might just pull this thing apart. I'm pretty good with the mechanical side of things.

Gregg K

I just disassembled the switch, and it's like new. Put it back together, and the problem is still occurring. It's not the switch.

Mrmerlin

what was the last thing that you fixed has the HL relay ever been replaced?

Gregg K

No relays have been changed. This instrument light problem happened half way through a trip I took. It happened without any intervention.

Ed Scherer

Check the instrumentation lighting dimmer rheostat. Roll it back and forth a few times. If that doesn't work, try removing the connectors (two spade-style connectors for your '89) to it and short them out (connect them together with a short piece of wire).

IMHO, the dimmer rheostat is more likely to fail than the headlight switch.

Some threads you might want to review:

• Dash light dimmer
• No Dash Lights Any Ideas
• Could somebody please measure resistance of up-to '88/'89 dash illumination rheostat?