Porsche Enthusiasts Club Forum

Spent the day pulling the dashboard to bits to try & fix the instrument lighting. The bulbs in the dash work ok. But nothing from the gauge cluster. Can't get a meter on the contacts when it's connected as it's so tight in there. Replaced the PCB on the back of the gauges & replaced all the blown bulbs. So now the pad wear indicator is alight! (One of the pad sensors is wiped off so that makes sense.) Also the voltmeter is much more optimistic now!
What I don't understand is that some instrument lights work & the others not. All fuses are ok. Wondering if it's the potentiometer or the relay for it? But shouldn't that dim all the instrument lights? Checked the leds on the battery & they are fine.
Wonder if anyone has had a similar problem? Ideas anyone?
Had to put it back together as I need it tomorrow. But getting fed up of guess my speed when it's dark.

Are the bulbs in holders?If they are then the holders get a poor contact over time & you need to clean them up. Also clean the PCB with an ink eraser NOT wet & dry! Not done the 944 yet but the TR7 was a Royal PITA

I agree with Jim; the bulb holders can get a poor connection with the PCB. I cleaned mine and also tightened up the connections by bending the tabs on the bulb holder slightly and that cured an intermittant non-functioning bulb I had in my cab.

I'll add, replace ALL the bulbs as they tend to age & dim over the years.

Thanks for the replys. Will have another go tomorrow. Spent more time rebuilding the cluster than fitting it & at least everything else now works! (It was cold out there!) If I can't get any power to the holders will wire them direct to a spare bulb holder??? That was in there behind the cluster anyway. Not convinced theres any power there at all. Bulbs are replaced with LED's but the originals didn't work at all before so maybe somthing else.

Have you got the LEDs the right way round?
Don't forget that they need to have their positive leads connected to a positive supply and negative to negative or they won't light unlike normal bulbs.

Yes I tried them both ways to be sure but no difference! Just no power. Ran out of daylight yesterday. Want to see if power comes out of the potentiometer. The lights feed off two pins on the rh plug & it's dead.

Hiya.

The negative leg of the LED is usually denoted by a 'flat' on one side of the LED housing itself. It may be possible you could have damaged the LED if it's been connected the wrong way round. They don't like it up 'em so to speak. I assume these LED's are ok with 12V? I know the LEDS's come in various voltages. Bad earth somewhere?? Hope this helps and good luck.

Ben

LEDS are fine. No power there to damage them. They are the shape of the perspex widget. My meter died today so can't fault find until I get another. Gave it a wash instead. Passenger sill looks a bit iffy so will be off to the bodyshop soon.