Dash lights & Switch

[Beaky]

My interior dash lights (these are LED’s) have recently started to annoyingly constantly flicker.

First it was just the one bulb now several are doing it, by adjusting the dimmer setting they stop for a while then start flickering again.

Now I assume it’s the 30 year old dimmer circuitry that’s now malfunctioning and a new switch is in order.

As I always have all my cars dash lights set to maximum, I don’t care for or need the dimmer option.

Is there just a simply Porsche "on off" replacement switch that can be purchased or do I need to decommission the dimmer function on a new or on the old switch for that matter or can the dimmer element be by passed?

Regards

[fanaudical]

Interesting - the "dimmer" is just a variable resistor in the switch.

Is the flickering "constant" (meaning equal time on/off) or "intermittent" (meaning there is no discernible pattern to the flicker)?

[DRACO A5OG]

You could remove the switch, marking all the wires and inspect the rheostat. But before that I would check all the grounds to insure they nice and free from corrosion. If you have not do so, I would install a inline fuse as the black/blue wire is not fused.

[kidrock]

try dousing the rheostat dimmer switch with electrical contact spray before doing anything else...it's probably just dirty.

[timmy2]

If you want to bypass the rheostat just move the black/blue wire over to the grey wire terminal for the running lamps. You can look up the terminal number for your year to confirm. Fusing is always a good idea.

[Beaky]

Originally Posted by fanaudical

Interesting - the "dimmer" is just a variable resistor in the switch.

Is the flickering "constant" (meaning equal time on/off) or "intermittent" (meaning there is no discernible pattern to the flicker)?

A bit of both but more than often its a constant flickering,

[Beaky]

Originally Posted by DRACO A5OG

You could remove the switch, marking all the wires and inspect the rheostat. But before that I would check all the grounds to insure they nice and free from corrosion. If you have not do so, I would install a inline fuse as the black/blue wire is not fused.

I have already installed the fuse, will check the earthing this evening

[Beaky]

Originally Posted by timmy2

If you want to bypass the rheostat just move the black/blue wire over to the grey wire terminal for the running lamps. You can look up the terminal number for your year to confirm. Fusing is always a good idea.

In terms of a by pass I believe my wiring is a follows:

N - Grey/White
58l - 2 x Grey/Black
58r - 2 x Grey/Red
75 - 2 x Red/White
57 - White/Green
58a - Red in line fuse and then to the Blue/Black from the loom
58 - 2 x Grey
56 - White/Black

So move 58a to 58, what do I do with the grey wire just tape that up?

[86 911 Targa]

^^^^^
For our '86.
Hope this helps.

Good luck,

Gerry

[timmy2]

Should have a female spade with a male tab available on your wire. If not install one. Then just double it up keeping the license lamps in the circuit as well.

[Beaky]

Originally Posted by timmy2

Should have a female spade with a male tab available on your wire. If not install one. Then just double it up keeping the license lamps in the circuit as well.

So has anyone tried this before (moving 58a to 58), does this work, and is there any issue about load on terminal 58?

Just a little concerned as I don't want to end up with fried wiring!

[timmy2]

Led lamp load is what?
Current load on that cicuit now is 2 incandescent lamps.
Pretty negligible added together...
The load of the dash lights is already going through the switch, just on a different contact.
Your only other alternative is repair or replace the switch.

Pop a couple of led lamps in the license plate holders and you'll be fine...

[famoroso]

Originally Posted by kidrock

try dousing the rheostat dimmer switch with electrical contact spray before doing anything else...it's probably just dirty.

Where? Spray in / above the exposed piece of fluted metal between terminals 58r and 75?

Originally Posted by timmy2

Pop a couple of led lamps in the license plate holders and you'll be fine...

Suggestions, or link, for quality LED license plate bulbs?

[Beaky]

Originally Posted by timmy2

Led lamp load is what?
Current load on that cicuit now is 2 incandescent lamps.
Pretty negligible added together...
The load of the dash lights is already going through the switch, just on a different contact.
Your only other alternative is repair or replace the switch.

Pop a couple of led lamps in the license plate holders and you'll be fine...

Will report back on Saturday once I have moved the wires

Thanks in advance

[Beaky]

So did this and still had some flickering, so can only assume its a dodgy connection or a faulty relay (if this is one!)

[timmy2]

Did the cleaning or moved the source wire?
If still flickering I am thinking it may be a ground issue.

[422flat6]

Are you sure the LEDs are dimmable? Many aren't.

[Beaky]

Originally Posted by timmy2

Did the cleaning or moved the source wire?
If still flickering I am thinking it may be a ground issue.

The moved wire, still need to clean the connections/grounding

[Beaky]

Originally Posted by 422flat6

Are you sure the LEDs are dimmable? Many aren't.

They have been working fine for several years, only stared flicking a few months ago,

Thinking about it I noticed the flicking after the car was laid up in the garage for a few weeks

[wwest]

Originally Posted by Beaky

A bit of both but more than often its a constant flickering,

Fairly common LED failure mode.