Electrical Help - Headlights

[psychonaut]

Can anyone advise whether a 1986 water-cooled 1900 RHD petrol has a headlight relay, or whether the feeds go straight from the switches on the dash, via the fusebox, to the headlights on the front of the vehicle?

I've been helping a friend with his van tonight that has a very curious headlight problem - i know what i'm doing with motorbike electrics but i'm finding 4-wheeled electrical systems slightly more confusing. You can't reach everything by laying on the floor next to it for starters!! Turn the light switch to sidelights or dipped beam and nothing illuminates at the front, although the tail lights are on. Switch on the foglight switch, and you get sidelights at the front, full illumination at the back. Pull the left-hand stalk towards you, al la flashing someone, and you get dipped lights at the front. Nothing makes the main beams illuminate, although the main beam advisory light on the dash illuminates as soon as the light switch is moved to any position away from "off".

The wiring behind the dash looks original, and is mostly held together by what appears to be the original cable ties. The wiring dropping down to the rear of the headlights also appears to be original and unaltered.

We're going to have another look on Monday evening, and trace all the wiring through to make sure nothing has been connected up to anything it shouldn't have been. In the meantime though, can anyone think of anything else that would make the lights behave in this way?

Can anyone give me any other pointers? Ta in advance

[AngeloEvs]

Lighting is through switch unless modified. I would be checking fuses, earths, the switch itself and that any non functioning bulbs were Ok as a starting point. Has this suddenly started or has the van been laid up for a while?

[psychonaut]

Lighting is through switch unless modified. I would be checking fuses, earths, the switch itself and that any non functioning bulbs were Ok as a starting point. Has this suddenly started or has the van been laid up for a while?

Hiya dood - i did continuity tests through the switch last night and when the circuits should be live dependant on the switch position, they are. The bulbs too are good, as are the fuses. I shall investigate the earth lead from the headlight wiring loom on Monday evening.

Thanks for the suggestions

[Grun]

Have a look at these 'crown earths' in fuse box area.
Front main/dip and side lights should all earth here. Tail lights earth at rear of van.


Mike

[psychonaut]

Cheers Grun

[weldore]

dont ya just love it when peeps go out of their way to take a photo of summink for ya

[psychonaut]

Is ace and no mistake Wellie - i can't think of may forums, even in my old haunts in the biker world, where people would go out of there way to do things like that

[Grun]

All part of the service chaps........... but must I hold my hand up and admit that the original photo was not one I took, but was saved from an earlier thread in case it could be of use to someone in the future. Saves a lot of searching (and typing).
Those earths are a good place to start, can cause all sorts of naughties with the electrickery.
Mike