Ackmann

I have a 1979 928 and I don't have any lights on my guages. All instruments work fine and I have checked the fuse and it is ok. I have played with the dimmer switch and it does seam to flicker the volt guage when I turn it one way or the other showing signs of some voltage change. I dont have a service manual yet and wanted to see if this easy to fix. (bulb or bulbs?) Where located?

Thanks

SharkSkin

Unless you have very small hands, changing the 3 bulbs along the bottom of the instrument cluster that illuminate the gauges usually involves removing the cluster -- details here. Note tht you have two "dimmer switches". One controls the wiper interval, the other controls the lights. Make sure you're fiddling with the right one. The dimmer potentiometer may be the problem -- try removing the two wires from it and shorting them together. Also see if you get 12v on one of the wires. If so, the problem may be the pot or the bulbs. If not, the problem is elsewhere, maybe in the CE panel or wiring, perhaps even the ignition switch(but double-check the fuse first).

Ackmann

Nice web site. Very helpful; thanks.

SharkSkin

Thanks... Any luck with the checks i mentioned? Also, you realize the key has to be on for the lights to work, right?

Hi Ho Silver

Ive got the same problem as this and its getting on my ****, however I can get my hand to get one of the bulbs out and back in, but it still doesnt work, we need a little tool to get at the other two I reckon, or mini me. Ive already had the dash out once by the way, but I will get it fixed, just after Ive put in my new brake master cylinder that Ive just ordered.

dbrown928

Are they completely out or just really dim? I have had success with my early car by recoating the "prisims" that carry the light from the bulbs to the gauge face. Strip the factory coating (silver paint) with acetone and recover with metal HVAC duct tape. It reflects the light much better and brightens things up considerably.

Ackmann

Completely out. All dash related lights and ***** are black at night. Exterior light are all good and all guages work good. I haven't played with anything yet except the fuse. I will clean fuse terminal and then check bulbs this weekend.

CAShark

I too am having the same issue. Although I was doing some repairs to some connectors. Would removing the "Warning Light" bulb cause the Instrument lights to fail? In a series of some sort. I also noticed my Auto Gear Selection lights are also not working.

SharkSkin

Do check for power at the potentiometer. It's easy to reach, and it's a very common point of failure. It's not a ground issue or your gauges wouldn't be working.

CAShark, you may have blown the fuse -- it's very easy to do.

CAShark

Thanks Sharkskin, I will check the fuse after work. I removed the warning light bulb and was wondering if it was not completing a circuit.

Ackmann

It turned out to be the pentiameter dimmer switch. Working again after some clean up of the contacts and fuses.

Appreciate the help guys.

SharkSkin

Cool... always try the easy stuff first!