Dash lights not working

[Westy End]

Hi all,

I have blown the dash illumination on my 1991 Vanagon (ie the bulbs that light up the dials not the LEDs in the centre panel/clock nor the temp warning light). I was replacing the bulb behind the heater blower panel and shorted those wires on the heater control arms . Bentley says that there is a fuse at position 16 for these bulbs but i have checked and this has not blown. I also found that there is a fuse at "position 58b" which is above the relay panel where a 10A fuse had blown but i have replaced it and the lights are still not working. Is is possible that i have fried the dash circuitry?

Any suggestions would be great.

Westy End

[marlinowner]

58b is the output pin of the dashboard dimmer built into the light switch, circuit goes from there to 10A fuse above relays, 4th of 6 locations just to right of centre. Shorting light on heater panel shouldn't affect instrument panel circuit as they are in parallel. If fuse is ok then check for voltage at fuse and 58b on switch, assuming sidelights are working.

[Westy End]

Ok - thanks for the guidance. too cold and dark to attack it tonight - will let you know how I go tomorrow.

[Westy End]

ok - some more information but not much progress.

sidelights working.

Voltage at 58b grey/blue connector at headlight switch is only 0.2 volts. Same at heater switch bulb. same at the fuse above the relays (although this has grey/white wires not the grey/blue stated in the manual Could it be a faulty earth? I havent traced all the way along the wires to earth point number 20 (for the dash panel) yet.

[marlinowner]

where are you connecting the -ve meter probe? if its directly to ground then you have a problem at the switch. are the number plate lights working? if so then check you have 12v at lighting switch output 58 to prove your meter is ok, if thats ok then take out switch and measure resistance between 58 and 58r, should vary with brightness adjustment. If open circuit that is the fault, you could short 58 and 58r together to see if that puts the dash lights on.

[Westy End]

Solved!

Many thanks Marlinowner for your methodical approach

I checked the numberplate lights - not working - that fuse is number 20 - blown! Replaced and now all instrumentation is lit. I cant make head or tail of how that fuse would control the circuit for the panel illumination but it does. Perhaps the wiring has changed between 1986 (which is the Bentley diagram I was referring to) and the later Vanagon.

Maybe the moral of the story is to check all fuses first and get the spaghetti wiring out if there is none blown.

Westy End