Aux gauge illumination problem

[AAH!]

I fitted a VDO boost gauge and for power I tapped into the wiring that feeds one of the 3 aux gauges at the point it enters the gauge.

Recently I have noticed that after the head lights have been on for a while, just the 3 aux gauges and the new boost gauge turn off, in fact they seem to quickly fade rather than just turn off. Sometimes if I turn on if the headlights on and off they come back on sometimes they don't.

Am i correct in thinking that aux gauges have their own power supply? Although this doesn't sound right, might it be overloaded with the addition of the boost gauge and might it be cutting out if it gets to hot? Or might I have just knocked something whilst fiddling around in that area.

Angus

(also posted in the VDO boost gauge - group buy thread)

[80Quattro]

Is your RS2 right or left hand drive as the aux gauges are different. Also which colour wire did you tap into for the boost gauge power?

[AAH!]

Its a RHD RS2

I can't remember which colour the wires were, but I tapped into the two wires that enter into the top of the oil pressure gauge, which I assume supplies the 12v dimmable power.

When working the boost gauge turns on and dims with the aux gauges.

Angus

[80Quattro]

There is a black/blue wire which supplies power to the oil pressure gauge and a grey/red one for variable power to the bulb so I think you must have used these two.

The grey/red wire comes from a booster for the lights on the 3 aux gauges so I would expect that it is the booster which is failing. I don't know whether this is because the boost gauge lighting has over loaded it or if it is just coincidence but you could either replace this and hope it all works ok again or use a different supply for the boost gauge illumination.

All the other variable illumination is supplied by the grey/blue wire. I am not quite sure why the booster is needed for the aux gauge lighting but you could try taking the supply from the grey/blue wire instead, it will still dim just like it did before although it might be slightly dimmer since it is not coming from the booster.

[HPmuirt]

I took the power feed from the heater illumination, as it was closer to the boost gauge position above, but when I plugged in the bulb of the boost gauge, it didn't illuminate, even though I had measured a voltage there.

I suspected that this was because there wasn't enough oomph in the circuit, so I tried an LED and it worked......hazzar!

Cheers n

Si

[80Quattro]

The heater illumination is supplied by the same grey/blue wire as the rest of the dash illumination, I'm not quite sure why it wouldn't be able to light one more bulb. Anyway, that is a good point about using an LED, the current draw is so small that it should not overload the booster. It could be a simple fix if the power for the bulb is being supplied by the grey/red wire.

[Jas11n]

Took my power feed from the glove box light.

[AAH!]

Thanks Guys

I will try the LED option and if that fails rewiring as per your suggestions.

Angus