no mainbeam, V40, 1999

[nilotic]

Hello

Over the course of a month I noticed an intermittent headlamp fault, which is now a permanent problem. All other electrics seem fine.

Initially the dashboard main beam light was feintly lit and one headlamp (drivers side) was failing to light brighter than daytime running setting.

Now the dashboard main beam light is always fully lit, and both headlamps refuse to light any brighter than daytime running setting. So I can't see where I'm going in the dark, and I can't flash / use mainbeam.

I'm pretty sure it's not a fuse or bulb because for one brief journey yesterday, I was back to one headlamp as normal. I'm guessing it's an earth connection or perhaps the ultra-costly electronic control module.

Any advice would be gratefully received.....where should I start ?

Nilotic

[billofdurham]

Have you checked for 12v at the headlights, especially the one that was not operating at all?

Also check the operation of the main light switch and the main/dip beam switch.

As for the earth - each light unit has its own so I would not have thought that a bad earth on one unit would affect the other.

Bill.

[MadeInJapan]

Have you attempted to replace the light bulbs?

[nilotic]

Thanks for the replies,

BillofDurham:
- Haven't checked the voltage at the lights - yet.
-I think the main switch and dip/main beam switch are OK although I notice the green light is lit under the main switch when its at '0' -- I suspect it shouldn't be, I think this green light means the lights are on full (dipped) mode. It (and the main beam dash light) go out when P(arking) is selected at the main switch. The headlamps are still dim but the rear lights are normal.
-OK thanks I guess it's not an earth problem.....

MadeinJapan :
- No I really don't think its the bulbs. When one headlamp suddenly did work again, I ruled this out.....

It's behaviour seems to be 'decided' when I turn the ignition on - I either have constant fullbeam dash light bright and no headlights, or dim (constant) fullbeam dash light and one light operational - dipped and main behave as normal for this one light when this happens.

[billofdurham]

I think this green light means the lights are on full (dipped) mode

If this is like the 850 the green light indicates that the day running lights are on.

I would still suspect the main/dip switch as it is possible it is sticking between positions.

Bill.