DrScientist

well, it's been 4 months into ownership, ~6k miles (yes i know), 1 oil change, unfortunate rock chip on the front bumper, cracked shift boot base, blown taillight bulb, broken power window switch, and lots and lots of smiles.

but... have the electrical gremlins started to set in?

sunday afternoon, car started normally, but when i turned on the lights (parking or headlights), the backlighting for the instrument cluster went totally off. (they had previously only dimmed when the lights were turned on)

luckily its an 89, so i at least could see my speed and miles to empty in the digital readout, but a completely dark instrument panel seemed a bit dangerous.

all other dash lights seemed to operate normally on startup.

then... 24 hours later, on a long drive at night, the light just came back. with no apparent rhyme or reason. havent driven it since.

sounds to me like a ground somewhere, but which? where? what do i a tackle when this comes up again?

(also, are there electrical diagrams by model year available for download somewhere?)

Randy V

Sounds like a faulty fuse.

Check the fuse layout located either in your Owner Manual or attached to the main CE board cover.

Replace the fuse dedicated to the instrument panel lighting.

RFJ

If the dimmer is like the early cars it may just need cleaning or what Randy said.

MainePorsche

The illumination for the backlighting of the cluster, the pod switches and the center console run through Black/Blue wires which originate at the dimmer switch. The are two Black/Blue bundles connected there. One for center console, the other for the pod. They attach via spades. Make sure they are fastened well, and you may want to clean up the rheostat wheel - can increase resistance if not 'electrically clean'. If you want optimal amperage for all illumination, attach the the two Black/Blues to the Black wire that feeds the rheostat. Eliminates potential resistance, but will also eliminate dimmer function.

kos_007

Possibly the "load resistor" - it is a coiled wire resistor with a bimetal safety switch underneath. The current flows from the dimmer rheostat via the resistor to the instrument lights when the main light switch is in position 2 or 3 (outside lights on). The resistor is mounted to the brake pedal bracket - up high , close to the firewall. You need to remove it, open it up and clean/adjust the contact points.

MainePorsche

I thought it was an MY 88.
My bad

kos_007

To troubleshoot you need to check voltage on both leads of the rheostat/dimmer with the main light switch in position 2 or 3. If it's 12V on both leads and still no instrument lights then the load resistor is the culprit. Locating and removing it is the main challenge. You need a flashlight and a 10mm socket with extension. With your head on the floor next to the brake pedal look up - you should be able to see it next to the brake pedal bracket, close to the firewall. It is held in place wit a single M6 (10mm socket) nut.

STRIKEMASTER

I have the same problem with my '83, instrument lights dim/out . I got a 12' strip of LEDs, ran the wires to the dimmer input side and then wedged the strip into the gap that I have between the bottom edge of the pod opening and the instrument cover glass. Works great and doesn't reflect onto the windscreen. Took about 10 minutes to put in, cost about $6.