Headlight faliure in the dark in the middle of nowhere....

Post by **mrnickmuss** » 13 Nov 2014, 17:54

I have a 1991 Doka when driving home this evening I went to put my headlights on full beam and I lost all front lights.... Not great in the middle of nowhere!
When the ignition is switched off side lights work. Dash lights working and full beam blue light stays on and wont switch off. All fuses fine any ideas?
Thanks in advance!

Post by **CJH** » 13 Nov 2014, 18:38

I've heard that the headlight switch can melt, due to the high current drawn by the lights, but I don't know what the symptoms of that would be - might depend on what bits melt I suppose. The long term solution, if that's what's happened (and apart from replacing the switch obviously), is to wire the headlights via relays, so that the only current flowing through the switch would then be what is required to trigger the relays, which is negligible.

Post by **mrnickmuss** » 13 Nov 2014, 19:11

Thanks CJH, for the reply, were is the switch located? Is it in the steering column?

Post by **CJH** » 13 Nov 2014, 19:26

I meant the one in the dash binnacle.

Post by **MidLifeCrisis** » 13 Nov 2014, 20:21

It might be useful if you can elaborate on exactly what the current status is ...... as it doesn't really make much sense at the moment;

With ignition off;
1) with headlight switch off what is on/not on
-a) what changes when you pull the high beam stalk
2) with headlight switch in first position what is on/not on
-a) what changes when you pull the high beam stalk
3) with headlight switch in second position what is on/not on
-a) what changes when you pull the high beam stalk

Now with ignition on;
1) with headlight switch off what is on/not on
-a) what changes when you pull the high beam stalk
2) with headlight switch in first position what is on/not on
-a) what changes when you pull the high beam stalk
3) with headlight switch in second position what is on/not on
-a) what changes when you pull the high beam stalk

Post by **mrnickmuss** » 13 Nov 2014, 22:05

Thanks for taking the time....

With ignition off;
1) with headlight switch off what is on/not on

Nothing

-a) what changes when you pull the high beam stalk

blue light on dash stays on and wont switch off

2) with headlight switch in first position what is on/not on

Nothing apart from dash lights and blue high beam light

-a) what changes when you pull the high beam stalk

Nothing changes

3) with headlight switch in second position what is on/not on
-a) what changes when you pull the high beam stalk

the only thing i see is the blue light on dash getting brighter no main/high beam lights at all

NB. However when I was trying to do a roadside diagnosis my side lights did come on when I had the igntion off but as soon as turned the ignition on they switched off. but now home on my driveway nothing.

Now with ignition on;

Exactly the same for all as above apart from blue light on dash not brightening but staying on

1) with headlight switch off what is on/not on
-a) what changes when you pull the high beam stalk
2) with headlight switch in first position what is on/not on
-a) what changes when you pull the high beam stalk
3) with headlight switch in second position what is on/not on
-a) what changes when you pull the high beam stalk

Post by **MidLifeCrisis** » 13 Nov 2014, 23:58

That's still really odd but the only scenario I can think is that the ground(s) for the headlights have failed - that's the only way I can see that the highbeam indicator light would be on without highbeams being on (assuming the bulbs are good); and also that the dash lights can be on but the sidelights aren't on (again assuming fuses/bulbs are good);

You could try measuring voltage at the bulb connectors to see if 12v is reaching the bulbs - you could also check the continuity of the bulb grounds to actual ground to test if they have failed?

There's also a chance that the highbeam stalk has failed in some way but I'd start with the bulb grounds first and work on from there .....

Post by **mrnickmuss** » 14 Nov 2014, 06:57

Thanks, I really appreciate your input, I will get onto it armed with your info.... I will report back when I know more!

Post by **clift_d** » 14 Nov 2014, 07:57

We had issues with our headlights that were resolved by cleaning the connections to the earth crowns under the dashboard.

Post by **mrnickmuss** » 14 Nov 2014, 18:01

Spent a few hours on this today my mechanic friend, had a look between his other booked in jobs and I picked up where he left off.....The switch has definitely seen better days but seems to be working but will replace as soon as I can. but the main fault seems to be that the earth feeding the main lights is live.
Wondering if this could be a fault from the dipper switch on the steeering column???

Post by **MidLifeCrisis** » 14 Nov 2014, 18:26

I'd imagine that it is live because it is no longer tied to a ground so it is 'floating';
With all power off, can you test for continuity of the headlight ground terminal to van ground?

Post by **mrnickmuss** » 16 Nov 2014, 19:47

havent managed to get back to sort my van I have a question which someone might be able to help, I will be really impressed if the can....
My Doka's is a 1991 model and has square lightls fitted after rumaging behind the front light I belive these to be a retro fit as there is some 'additional' wiring (which isnt live) and the mountings look like there has been some small modifications made to make them fit. the current and possibly faulty light switch is part number: 251 941 531 Q . The only ones I can find listed online have the same number but finish with an 'M'. Can anyone tell me what the difference is (if any) and could I replace mine with an 'M' switch.
i look forward to a reply by someone with a superior knowledge!

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