Full beams staying on... help required!

[Rich135]

Hi All

I have a strange problem which caused a flat battery yesterday on my 1970 +2.

When the engine is running, if I pull the headlight button to activate the main headlight pods, they go up fine and are on the normal headlight setting without full beam. The full bream stalk at this point is in the down position on the left of the steering wheel.

If I then push the headlight button back in to put the pods down, the light pods go down, but the full beam lights come on in the pods, even though they are in the down position (I can see them through the body work from the outside). They will remain on until I put the full beam stalk up, and then down again.

Pressing the "off" on the side lights has no effect on then.

All a bit strange but I am guessing I have a relay that needs replacing? Are the full beams normally only on when the full beam stalk is in the Up position?

Many thanks

Rich

[billwill]

Check the two micro-switches that are operated by the headlight pods. They are crude construction and likely to be the source of your problem.

One of them opens when the pod is down and this is supposed to release/open the headlamp relay.


PS: your symptoms are very strange, I can't think of any way that a wiring short could make those symptoms, but I think there is a short or wrong wiring somewhere.

Did this happen of its own accord or did you change something in the wiring before you noticed the effects? If you pulled wires off the headlamp relays to investigate a fault at the early stage you may have put them back on the wrong terminals.

[Rich135]

Thanks Bill, I will have a look at those switches when I am at home on Wednesday.

I haven't done any fiddling at all on the wiring, so it might have been like this for years. Normally I remember to turn them off again, but I forgot on Sunday, whoops!

[Robbie693]

I think there was a 'feature' on the early Plus 2's that enabled the headlights to continually flash when the pods were actuated without the light switch being turned on first. Or something like that. Could this be related to the symptoms?

[Washer]

Hi

There do seem to be a number of different wiring standards for the +2, but I assume that in addition to the normal main/dip headlamp control you also have the 2 systems that are initiated by the 2 headlamp pod micro (1960s micro!) switches.

System 1: The headlamps only have feed to the dip/main switch if the lighting switch is on main AND the pods are NOT in the down position.

This system uses on the pod micro switches and a relay in the circuit between the light switch and the column dip/main switch. I am fairly sure that this relay is behind the dashboard (this is missing together with the micro switch and the wiring has been bridged on my +2). The pod micro switch makes/breaks an earth to operate this relay. The wiring diagram is not definitive and it is possible that depending on the relay type either opening or closing the micro switch will inhibit feed to the dip/main column switch.

System 2: The headlamps will flash the main beam if the lighting switch is off AND the headlamp pod is raised.

I am not sure if the headlamps flash when only side lamps are on; it seems to be a reasonable thing to do as the pods should be down. There is separate micro switch that earths a relay in the engine bay to operate this system, together with a separate bimetal ?flasher? unit in the circuit between the micro switch and the relay
As in System 1 it is not clear to me whether the headlamp flash operates when the micro switch is made or open.

In regard to your problem it is likely, as Bill has proposed, that you have problems with the micro switches System 1. The pod micro switches are rather crude mechanical contraptions and have plenty of scope for failure. I notice you state that it is the main beam that is on when the pods are down, if it was the dip beam then you could probably rule out System 2 as this only affects the main beam. Maybe you should check if either dip or main beam can be switched by the column switch when the pod is down.

If you confirm it is main beam and dip switch will not operate when the pods are down then you have a problem with System 2. In fact you may have 2 problems with System 2 as the main beam should also flash if system is feeding the main beam lights through the relay.

At the moment I am in the process of fitting relays to remove full current going through the dash switches and I am contemplating if it is worthwhile restoring these 2 systems on my +2 that the P/Os have removed. It seems that the systems provide little useful functionality for me but a lot of potential for failure just for the sake of originality.

I hope this is of some help to you

Mike

[Rich135]

Thanks Robbie and Mike, that gives me lots more to go on when I get a chance to have a good look around the front end/wiring.

Electrics are not my strong point, but this will be a chance to learn more! I will report back with any findings.

Thanks again,

Rich