lights and fog lights

[tdafforn]

Hi All,
With impending Winter here in the UK, my mind is on things electrical (lights that is).
I have always had a problem on my plus2 with main beam.
When turned on it is fine for 30 seconds and then all lights go out and the headlamps drop back into the bonnet (Scary on unlit roads!!).
After a while (15 secs) the lights come back on and return to the up position.
I think I traced the problem to the voltage cutout behind the dash. However Rather than digging it out I have been wondering whether the problem is a defective component or some added load on the circuit...
Anyhow I have done some more thinking over the summer and have noticed that on full beam the headlights and fogs are on. There is a button on the dash marked Fog lights, but it has no effect in any position.
Should the fogs be wired to the headlamp circuit through the cut-out?
If not, I guess that this extra load could be flipping the cutout?
In which case how should the fogs be wired? (its not clear from the circuit diag I have!)
Cheers for any help
Tim

[Robbie693]

First of all check your light switch...

I had a problem which sounds similar to your own; lights going up and down, on and off.

Turned out to be a plastic bush in the light switch which had cracked and was intermitently sending current. Bit of araldite did the trick!

[Hamish Coutts]

Tim,

Isn't it a joy to be approaching a corner at speed, in the dark - and all the !%$$?*! lights go out. This of course, always happens on a road you don't know very well and it's probably wet & slippery.

Obviously something is drawing extra power from the lighting circuit causing the trip to operate. It should function with all lights on.
Check that someone has not fitted 100/80w headlight bulbs because that is easily enough to do the damage (from hard experience). It is also risky as if this is the case the wiring will be overloaded.
I had the same problem when I replaced the standard instrument lights (2w) with 5w. The extra 24w load was enough to fire off the trip. The trip seems to be very sensitive.
The fogs should not come on with the main beams either. They should operate from the dash switch only.

A solution is at hand though. In a word relays. Use these little beauties to switch the lights (and any other heavy amp circuit). It removes a lot of current from the lighting circuit and is a lot safer. Properly wired the voltage drop at the bulb should be a lot less giving brighter lights. You'll need 3 - one for the dip, main and the fogs. While your at it, you might as well get a fourth for the fan.
I also have one rigged up via an oil pressure switch to control the electric fuel pump. When there is pressure the pump works. No oil pressure and the pump stops. Handy if anything happens - I dont want the pump merrily working away if I ever have an accident, perish the thought.

Relays will also allow you to fit stronger bulbs if you want to because they will be powered from a completely independent, fused circuit. All the safety trip will see is the relay operating coil (about 5 to 10w) and not the lights so should behave itself.

If you want any more info, give me a shout.

Regards,

Hamish.

[types26/36]

Isn't it a joy to be approaching a corner at speed, in the dark - and all the !%$$?*! lights go out. always happens on a road you don't know very well and it's probably wet & slippery.

if I ever have an accident, .

Hmm! maybe that should read "when" and not "if"
Brian

[tdafforn]

So let me get this right...
The fogs should only come on when the switch on the dash is pressed.
Are the fogs in any way connect into the head light circuit?
Eg can you turn them on and off independent of the head light switch or are they disabled when the head lights are off?
Cheers
tim
PS first time I lost the lights was mid bend, darkest november with ice on the road. Almost needed the seat re-covering!

[Hamish Coutts]

Tim,

It's not much fun loosing the lights at night, it doesn't half dent your confidence in the car.

To the best of my knowledge the fogs should be independent from the headlights. (logical as they should be used in bad weather when the headlights would create too much glare) The only thing they have in common is the power supply. Mine can be switched on independently from the headlights.
One thing I haven't checked is if they go out when the headlights come ON. Don't think this is the case, though. I'll try it and see what happens. I'll also have a look at the wiring diagram.

Regards,

Hamish.

[M100]

Conventional lighting practice to comply with UK construction and use regulations would have the fog light switch feed wired from the sidelamp switched output.

I doubt it's been done like that though!

I remember a long time ago looking at an S1 wiring diagram and thought, despite the lack of fuses, how logical it was. I progressed to the S4 and thought, that's a bit of a mess and still not many fuses but it's almost logical (yet still a crap diagram)

.......the +2S's looked worse than spaghetti knitted in a blackout.

[chrishewett]

I also have had the bowlchurning experience of loosing the lights mid-bend in the rain!
I would very much recommend converting the headlights to failsafe and using relays. You can then uprate the bulbs to something better than the 2 candlepower setup originally fitted!
It wasn't cheap but about the best money you will ever spend on the car.
Chris

[bengalcharlie]

Hi Hamish,

you are telking about relays for the headlights but I believe relays are already fitted from the factory, is it not?
If not so, where did you fit these relays because I do not see anything in the dark with my 75 w sealed beam headlights and I have to fix it, that is for sure.

PS nothing to do with this subject but I have ordered some solid drive shafts with cv joints and I am very eager to feel the difference.
If anyone is interested about my experience feel free to contact me.


cheers

Robin

[tdafforn]

Hi,
On my plus two the lamps are failsafe, my guess is that when the cutout operates it also trips the solenoid circuit..
If the fogs where powered through the side light circuit then would they still draw current through the cutout?
CHeers
Tim
PS relays may still be the way to go, although not nessecaryly for fitting brighter lights as the combination of main beam and fogs is pretty bright on my car!

[Hamish Coutts]

Tim,

You're right, the solenoid is part of the lighting circuit and so will be switched off when the safety trip operates - thus lowering the lights. To the best of my knowledge the fogs are independent of the side light circuits as they draw too much current.

I still say that you should fit relays to all heavily loaded circuits. Your lights will be even brighter!

Hamish.

[Hamish Coutts]

Robin,

I have yet to see a +2 with headlight relays fitted by the factory. Mine's a Nov 73, +2 and didn't have them fitted.

Regards,

Hamish.

[carrierdave]

Good morning
Are you talking about the +2s or the +2s 130 ? I have the former that runs from two switches under the right hand side of the dashboard; one being driving lights the other being fog lights. These are fed from the center fuse box and are on the same circuit (power supply) as the rear lamps.

There should be a blue/yellow and red/white cable within the wiring loom behind the spot lamps. One side connects from the spot lamp one from the fog lamp ? Why both lamps are switched independently of each other baffles me!

The best thing to do is remove the feed to the lamps from its current position - get a volt meter and connect one end to an earth and then put the other probe into any open connection (where there is a wire in to the connector but no wire out).

Then turn on the switches ? If you already have 12 volts and this goes when the switch is changed then you have your supply. If nothing happens then keep looking.

I will check the position of the wires in my car tonight and let you know.

Dave

[tdafforn]

Problem sorted...
It looks like the DPO wired the fogs into the driving light circuit in order (I guess) to make full beam really bright!
Anyhow this configuration obviously draws much more current through the cut out setting it off. Looking at the circuit diag this would also cutoff the supply to the solenoid valve for the vacuum circuit opening it up to the vacuum and hence dropping the head lights!
So problem sort of solved.
I disconnected the fogs and now the lights stay on main beam without turning off (result!)
Now I just need to reqire the fogs to the correct circuit. (there are two suspicously disconnected wires behind the fogs!)
Cheers for all the help
Tim