Electrical problem - no lights

[ABMM]

Guys,

I'm posting this here because it looks like my shorty forty's had her electrics hacked and the manual is no help.

Here's the problem:

Lights don't work - low beam, high beam, spotties.

Dash lights work (apart from hi-beam indicator).

Fuses are all good.

Anyone able to offer some guidance on how to diagnose what's wrong with it? I could take it to an auto leckie but that's a last resort. I need to learn the electrics myself and troubleshooting helps.

Maybe a related problem - whenever I plug my 12v laptop power supply into the cig lighter it blows a fuse in the power supply immediately. I've tried standard 15A fuses right through to 25A - all blow instantly. Reckon it might be related?

Cheers.

[chimpboy]

What's the history? ie did they used to work and don't any more, or you got the car that way, or...?

[ABMM]

They were working fine the day before yesterday. Went out last night and when the time came to go home after dark, I noticed I had no headlights or spots.

The light switch is stock and the instrument cluster and parking lights come on when it's switched on full or half.

[-Scott-]

I don't know how a 40 series works, but my Sigma uses a relay to supply power to the headlight circuit - the relay won't turn on if the ignition isn't on, so I can't leave the headlights on, only the parkers.

If the 40 is the same, that relay would be the first suspect.

[chimpboy]

Yer I reckon turn on the headlights at the dash, get out your multimeter and start checking at the headlights working your way back towards the switch.

[ABMM]

Thanks for the advice guys. I had a thought it might be a relay so I'll check that first before breaking out the multimeter and having a go at chimpboy's idea.

Cheers.

[ABMM]

Relays are all good. Before I go untaping the wiring from the lights to the switch and back to the battery, is it possible that the light switch itself is buggered? If so, are they easy to repair?

Cheers

[chimpboy]

Relays are all good. Before I go untaping the wiring from the lights to the switch and back to the battery, is it possible that the light switch itself is buggered? If so, are they easy to repair?

Cheers

Yes but it's doubtful that's the problem if your instrument panel lights come on when you turn the switch.

Don't untape yet, start by checking voltages at each connection point. You can tell if the switch is working by checking what happens at the relay base when you turn the switch on.

[ABMM]

Update:

Thanks for your help guys.

No change in the situation. I've had lostmarbles from over on ih8mud looking into it (link: http://forum.ih8mud.com/40-55-series-te ... ights.html ) and I think I've just confused him as well as myself. No lights.

Cigarette lighter is pissing me off because to get at it I'll have to remove the heater and the stereo. I'll be plugging that hole when I'm finished and putting the friggin lighter port in the console. Blew more fuses in various accessories tonight and when I tested the lighter port with the multimeter it blew the cigarette lighter fuse.

The fusible links have been removed by the PO and some fuckwit has wired in an alarm at some stage - very secure - unplug two leads into the little black box zip tied to the hand throttle in full view and no more alarm. WOFTAM.

Here's the state of play so far (when various switches are turned on):

12V appears at either side of the 15A headlight fuse in the fuse block.
12V appears on the headlight switch - all modes except "off".
12V appears either side of the fuses the PO has used to replace the fusible links.
12V does not appear either side of the ammeter fuses.
12V does not appear at the headlights.
12V appears at the parking lights
12V appears at the tail lights and numberplate light
12V appears at the reverse lights
12V appears at the blinkers/hazards

[hj 45]

Check the combination switch in your steering column, you'll need to take the plastic cover off and have a looksee. That switch, which controls high to low beam and vice versa, directly switches the 12 volts going to your headlights, if the headlight loom is stock, there's no headlight relay.

Hope this helps.