Dashboard Switch Backlights

[craigwalton]

Hello,

Are all 4 switches (lights, hazards, demister, fog lights) on either side of the instrument binnacle/cluster meant to have backlights which come on once at least the side lights are turned on? My light switch backlight (ironic, I know) is the only one which doesn't come on.




New entire light switch unit seem to be reasonably priced (£9 at VW Heritage). This particular one looks to be for a LH drive car though. I'd feel better if I was able to replace just the backlight and not throw away an entire mostly functioning unit.

Does anyone know what bulbs (LED?) are used as the backlights, if they're easily replaceable, and where I could find one? Cheers!

[Blueshark]

Check the bulb at the back.

Joost

[craigwalton]

Thanks for that - I had not realised that the bulb was part of the red connector and not the switch unit itself! Have ordered a new bulb with plastic casing & connectors, should be here later this week.

[james butler]

i dont think ive ever noticed if the switch gear was backlit.
i bet all of mine are blown and have been since before i owned the car and ive never noticed!
im gonna have to check now.

[mark1gls]

The headlight switch does have a bulb in which should come on as soon as the ignition is switched on so you can find the light switch in the dark but it does mean it's on all the time you are driving so that is why the bulb is usually blow.
The rear heated screen and fog switches have bulbs built into the switch which you can not change very easily, they come on with the lights. The hazard light switch has a bulb which is separate to the switch similar to the headlight switch and like the other switches lights up with the headlights on.

[craigwalton]

Thank you for that knowledge Mark! Similar to you James, I wasn't sure if the light even had a backlight.

[craigwalton]

My stupidity has shone through as I took out the old light switch lightbulb and left the connectors dangling, they must have touched while driving, causing a short circuit. Ideally, fuse 14 (20A) would have blown but no, it melted for some reason without breaking circuit. Resulted in some smoke from melted wires. It also seemed to have broken the heater blower motor. I've replaced motor so blower is working again. The simplified circuit I've traced out looks like this, with the red denoting the melted wires.

circuit-melted.png

1. Is this light bulb indeed meant to be part of the circuit of fuse 14 (20A) which powers the heater blower motor?
2. The fuses were cheap eBay ones - is it common to have bad/faulty fuses where the plastic melts? Or is it more likely that fuse contacts were dirty so wasn't conducting well?
3. To replace the wire which has melted, is is sufficient to get any > 0.1A rated wire since the bulb is 1.2W / 12V?
4. The melted brown wire out of the lightbulb goes into a bundle of 4 brown wires where the cores are united together over about 1cm, covered in tape then split back into 4 wires. Why would a previous owner have done this?

Here's the heater blower motor switch. 3 wires on right are to motor's resistor pack, red/black wire is from fusebox and meted yellow/black wire to light switch lightbulb.

melted wire.jpg