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MG Midget and Sprite Technical - Headlights Failed

Here's what happened.

1. I switched on my headlights to drive home - no problem

2. I pressed the dipswitch to get full beam - everything went dark.

3. Quickly back to dipped - OK. Drove home like that, not daring to try again.

4. At home, tried dipswitch - no full beam. Pushed dipswitch again - no dips either.

5. Since then, no headlamps. Sidelights are OK.

This is Cherry, by the way. Frog.
Nick

sounds like a melty switch maybe? I had exactly the same main beam issues and found that the switch was melty. Got another one from a Bedford CF and fitted a relay - so far so good.
Rob Armstrong

I suspect that your dip switch has failed.

Whether it is a floor mounted, or a column mounted switch, the most likely way for the lights to go out like you describe is if the switch contacts inside of the switch came adrift and stopped connecting (first one, and then both main and dip beam don't work).

Looking at the wiring diagram, any scenario that would include a blown fuse would have had different symptoms (either both would go out at the same time, or on later systems, anything that could cause one to stop would not affect the other ("effect" the other?).

Alternatively, a failed light switch would have made both go out at the same time, or would have left the main beams undisturbed.


Try this test: pull your "flash to pass" on the turn signal stalk and if your main beams flash, then I am sure that the problem is inside of your dip switch (the power supply to the "flash to pass" switch is separate from the supply to the dip switch).


Norm
Norm Kerr

and now just for the record...
Halogens fitted with out relays ??
Onno Könemann

mine were...
Rob Armstrong

Sounds like the dip switch to me.
Onno. I've got Halogens without relays. Been in three years, done a fair bit of night driving,no problems. Have I just been lucky?

Bernie.
b higginson

I've had halogens (same power as the 'ordinary bulbs') for >5 years, no problem.

Agree with above... sounds like the dip-switch has taken a dive.

Think the foot-switch is a great idea... more convenient than the stalk... and they all worked the same way, too.

A
Anthony Cutler

That's what you get for not sending me a wedding using wedding cars tunbridge wells present!
Gary & Gaps

Yep I also have halagens without relays, curious Onno why you would imagine halagens were more of a load than normal incandescent bulbs? they take exactly the same amount of power.
Robert (Bob) Midget Turbo

I knew I should have wrapped that silver fish slice . . . . . . . .

Thanks guys. Looking at the dipswitch tomorrow - because my MOT is due on Friday.
Nick

Reminds me of an incident a few years back.. I had my first midget just at the end of uni, so whilst looking for a decent job, I was living in a grotty bedsit in Slough (if you've been there you'd understand)and my Midget was my only transport! I took my girlfriend to the cinema one evening. Rubbish film..got back into the car about 11 pm, started, lights on...nothing! Side lights only. Bolox. Called the RAC who kicked the tyres, tried to take the dash out and then disapeared and left me in a grotty car park in high wycombe withe the ferral locals circling.

So what do I do? I set off down the dual carriageway on side lights only, all going well as the speed builds, the first mile being flood lit. Suddenly, I'm doing 60, the light end and I realise side lights offer no foward vision whatsoever. Twitchy bottom moment, brakes, brakes...and..full headlight action restored! Now, I'm not religious but someone was looking after me that night. Turned out in the end it was a corroded earth.
Robin Cohen

And you say "same power" based on actual amperage readings or based on what some blighter wrote on a bit of cardboard box?

Bear in mind that, as the switch ages, the heat generated by the resistance in the contacts increases. Add to that the fact that replacement switches, at least on my side of the pond, are not nearly so good as the originals, and it seems like a no-brainer to me to fit relays so that the original switches have a much-extended life expectancy. Relays are cheap and easy to replace and available at any FLAPS; not so with Spridget headlight or dipper switches.
David "relaying the good news" Lieb
David Lieb

I feel very guilty, but have only just got round to starting the checks.

The dipswitch works. I took it out, and everything's working well. I get continuity between the feed and the two headlamp circuits, alternately as I switch it.

But then I had to pack up and do something else, so not till tomorrow will I look at the switch. As some of you know, I am electrically challenged, so perhaps you can help:- if I put the prongs of the meter on the feed to the dipswitch and earth, and then switch the switch, will that tell me something?
Nick

If you select Volts DC on the meter (20 volt range?) and then do as you describe with the prongs then you should read 12 volts if the light switch is on. Then you can place a prong on the first wire after the switch and check if when switching you get 12 volts in one position and then in the opposite position you will get 12 volts on the other wire.

If you do not get 12 volts with the headlight switch on in the first position you described then you have a fault around the headlamp switch.
Robert (Bob) Midget Turbo

Hi
Did the same tonight and last night as I traced faults. In the end, with lecky circuit to hand, I used my jump lead from positive, then connected that to a length of house ring main cable to supply power to each wire as required. Worked a treat. Nick, if you want I could photo the arrangement tomorrow and send it over. Also have yopu got a lecky diagram - helps a treat although the colours might not match up exactly!!!"
Dave
Dave Price

That would be kind, Dave. therowlatts at btinternet dot com.

I dread getting the switch out, and not knowing what I'm looking at.

Relays sound like the right way to go, though. I don't like the idea of headlamps loading that little 50-year old switch.

Thanks Bob.
Nick

Nick - have you got an electrical diagram as well? if not - what car have you got?
DAve
Dave Price

It's a frog, Dave - and I do have a wiring diagram. But I am very thick - electrically.

The plot thickens:- the dipswitch is getting twelve volts from the light switch. Surely we can't be looking at simultaneous failure of all headlamps?

What simple test can I do next?
Nick

Are you getting 12v out of the other side of the dipswitch?

If yes, check further down the loom that you have 12v at the bullet connectors near the headlamps.

Not sure whether the Frog has a separate bonnet loom? If so, there will be another bunch of connectors to check.
Dave O'Neill 2

Again not sure of the frog loom from the dip switch, but had a total failure of lights, so many years ago !in my then tuned Morrie minor which turned out to be a set of bullit connectors on the bulkhead from the floor dip switch on their way to the light units.
Very inconvenient moment as I recall !!

R.
richard boobier

This thread was discussed between 09/05/2011 and 18/05/2011

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