How to test headlight switch

[badgerfax]

Evening all, Hope someone can help,
The instrument lights have decided they would not like to come on, The headlights work ok so the switch is doing that job OK.
The light on the heater/fan panel works.
Is there any way of testing the output of switch to the instruments?
Any other places I need to be looking at?

[1664]

I had this happen on my old van. It was the dimmer on the headlight switch so I by passed it (doesn't mean that's your problem too though).

The input to the dimmer is pin 58 of the switch and has a 0.5mm Grey cable connected to it.

The output from the dimmer is on pin 58b of the headlight switch and has a 0.5mm Grey/Blue cable connected to it which goes to a 10A fuse above relay position 4. This then feeds track 1 of the flexible pcb that plugs into at the rear of the instrument panel.

I'm working on the assumption you have the later fusebox with the blade type fuses rather than the round torpedo type?

Do you have a Haynes manual?

[Ralf85]

Has somebody accidentally moved the dimmer switch and turned the instrument lights down?

[1664]

Has somebody accidentally moved the dimmer switch and turned the instrument lights down?

I'm going to be SOOOOO embarrassed if that's the solution

[badgerfax]

Thanks for the replies,

Fuse box is early type with torpedo fuses, Vans an A Reg 83
I tried rotating the dimmer either way and its a no show

[MidLifeCrisis]

Could be a problem with the long white electrical connector that connects to the back of the instrument cluster.
Yank the cover off the instrument cluster and look down behind the instrument cluster and you should be able to see a white connector - that how to power (and ground) gets to those lights; try giving that a wiggle and see if it fixes the problem?

[badgerfax]

Ok so I've got everything apart and thanks to 1664 I have tested resistance on 58 & 58b and I have around 0.8 ohms when the dimmer is down goint to 24 ohms when up so can say the switch is dimming as it should.
Guess the next step is to make sure I have voltage at the multi plug.

[1664]

Ok, just re-read your original post. The heater controls lamp is working and that is fed from the dimmer (I think, frankly the Haynes early fusebox diagrams leave a lot to be desired) so check voltage at track 3 of the flexible PCB where it plugs into the white connector strip as mentioned by midlifecrisis above.

[1664]

Then, if you have a voltage there, remove an actual lamp and try it there - if you have a voltage at the lamp position(s) we have a crappy earth to deal with

[badgerfax]

Ok got 2 of the 3 lights working. 1 blown bulb and dodgy connections on the pcb were the culprit.
Not helped by the instrument panel "Dash insert" being badly cracked with bits missing
I also took the opportunity to repair the slow running clock.
If anyone has an early dash insert going??.....

Thanks for the advice