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MG Midget and Sprite Technical - Electrical advice - headlights

Chaps

Cannot seem to obtain high beam on the 71 midget. Controls are a two position switch on the dash which in position 1 - halfway down - gives parking lamps, and in position 2 - all the way down - gives low/dipped beam. This seems fine. However, pushing forward the indicator stalk or pulling it towards the driver - to flash - no high beam. Indeed it reverts to parking lamps.

The stalk switch seems OK. There is continuity, and I cannot see anything obviously amiss. Don't really want to take it apart either!

Where else should I be looking please? Loose wires at the headlamps, poor connections? Could the lamps not even have a high beam option?
Oggers

Oggers,
if you're sure it's not the stalk switch or its connections(?) then I'd have thought that leaves the bullets behind the grille, as it's both lights the double bullet connector on the blue/white wires would be first choice.

There's a wiring diagram in the Driver's Handbook of course.

Unless of course a previous owner has made alterations.
Nigel Atkins

Nigel et al

It is by no means standard, and has an Ashley bonnet. Wiring seeems roughly as per diagram, but not looked forward of the bulkhead just yet - seeking advice first as to where to look.
Oggers

small correction, they're not parking lamps they're sidelights. You are allowed to drive on sidelights on roads with adequate street lighting.
When you switch to main beam - either permanent or flash - the dipped beams are supposed to go out so that part is fine, it's just the main beams not coming on. Either both sealed beam units are faulty, or a wiring fault, or a switch fault. Do you have a test lamp or a meter?
David Smith

were not the "sidelights" originally meant to be left on when parked at night..I'm old enough to remember when this was a requirement..and hence the panel light switch was incorporated to help save a little bit of battery capacity..not to mention adding to the drama of night time driving down dark country lanes!
David Cox

I would get a test meter (or lamp), then pop a headlight out and test for voltage at the connector and continuity across the bulb.

Also have a peer through the reflectors in daylight, sometimes you can see the state of the filaments.

Could also just be dicky connectors, so if all checks out just give them a clean up with wire brush or emery, reassemble and cross fingers.

AdrianR

A common problem with the column switch is that the thin brass leaves that carry the contact 'buttons' get tired and loose their springiness. This happens over time, but is accelerated by overheating at the contacts and is a particular problem of some poor quality aftermarket ones. When this happens the contacts don't make a proper connection, although this can be difficult to see, and the main beams fail to work,or only work intermittently.
An associated fault is the blue/white wire connection in the switch comes adrift, again because of poor quality rivets.
GuyW

Oggers,
Had a similar problem where my main beam switched off when I signalled right.....gulp.I am not afraid of the oily bits but am not at all knowledgeable with the sparky bits but I felt it deserved investigation. I isolated the battery and took apart the cowl that covers the indicator and main/dip function. Close investigation with a magnifying glass showed poor contact of the fine brass connectors and it was resolved by judicious poking with a small ponity screwdriver. So having read a bit of your previous exploits I would suggest that you give it a go before ordering a new or second and item as back up.
Good luck,
John S
J Sloan

I had a similar thing on my 1275, it was a bad earth, the one halfway down the right hand inner wing.

Dave
Dave Barrow

A simple test is to swap the high beam and low beam wires at the bullet connectors Nigel mentioned, where one wire comes from the switch and two wires go to the headlights, so that the switch is back for high beam and forwards for low. If you still get low but not high beams the switch is okay and so is the wiring as far as the connector. In that case you'd need to check the headlight wires, bullet connectors and the lamps themselves. It's not uncommon if one side filament blows that a "spike" can take out the other too.
The bullet connectors can get pretty corroded and grungy and will appreciate a clean anyway, which might even fix it if you're lucky.
Just because there is continuity across the stalk switch doesn't mean it's up to the task of carrying the current required so it can be at fault as Guy described. The Lucas switches were impressively reliable but they weren't designed to last as long as they have. In that case the answer is to install relays which is cheap and easy. Or get a new switch set, which might not be as cheap and is certainly less efficient.
Some people don't like them (relays) which is fair enough, but the simple facts are that they preserve the switch contacts and improve the lights by eliminating the big voltage drop across the switch contacts.
Another quick first check is to see if the high beam warning light comes on even if the lights themselves don't come on. If it does there must be power going to and coming out of the switch.
Greybeard

Chaps

Grateful thanks - I will check out as advised. I freely admit I am an electrical numpty.

I do have a multimeter however, so how does one check the indicator switch to see if that is working correctly for the high beam?

Incidentally high beam warning lamp does not come on when indicator stalk is pushed forward.

Oggers

If you have no high beam indicator light coming on it means:
There is no power going to the high beam contacts on the stalk switch OR...
No power coming out of the stalk switch to the high beams OR...
The indicator is a dud.
The multimeter (or a test lamp) can tell you either way by looking for 12v between the relevant poles in the switch set and a good earth point.

If you try the swapping over test suggested earlier and find the low beams coming on with the stalk switch forward it means the contacts are okay for the high beams. That's probably a better test than the multimeter which might tell you there's continuity across the contacts but won't tell you what happens under load ie; with the lights drawing current.

If on the other hand you end up with no low beams in the switch forward position, but high beams on in the switch back position it's a fair bet that the stalk switch is unwell. But there's a better than even chance that the contacts can be cleaned up with fine emery and a tin of contact cleaner (or brake cleaner spray is good too, but don't go nuts with it). These spring contacts are very small and the lighting current asks quite a lot of them so they can get a bit burnt and the springs can weaken over the decades, which is one reason why I'm an advocate of relays. They give the switchgear a much easier life.

As Dave said it can also be a bad earth. I don't have a 1275 so I'm not familiar with where the lights are earthed on the car. On mine high and low share an earth connection so if it was that bad I'd most likely have no lights at all. The diagram I have seems to suggest your car should be similar, but I don't know because I haven't seen it in real life.

Personally I suspect the stalk switch or the one-into-two bullet connector in the blue/white wiring at the front of the car are the likeliest culprits. Good luck with this mate. It shouldn't be hard to find and fix.
Greybeard

Maybe two blown globes--or does it have a headlight relay fitted, is it clicking
Does the high beam indicator light in the dash come on,that will indicate if the stalk is ok
William Revit

I'd do the swap Grey suggests as a first because it's a real test and you're dealing with known facts rather than a meter test that needs knowledge and interpretation (and possibly further tests).

Worth wiggling bullet connects and the wires to then even before swapping connections. If you disconnect anything make sure it's clean, secure and protected before/after you reconnect.

I'm almost sure you've wire-wiggled a problem on your other Spridget before(?).

The change to an Ashley bonnet by a PO may have introduced other change/amendments (or it may not).
Nigel Atkins

Good catch Nigel. I missed the bit about the Ashley bonnet. That might well have entailed some shenanigans in the electric knitting.

Worth a word of caution about the bullet connectors. They can be a mite fragile and it's possible to pull the wire out leaving the bullet behind, which is a bugger. Try to wiggle them out gently with a pair of fine pointy pliers if you can. Then as Nigel says a thorough clean is an essential step.
Greybeard

I was thinking of a wriggle with precision instruments - fingertips, and using eyes.

If the wire(s) come out of the bullets then they needed replacing anyway.

As well as clean I like to add something to help prevent moisture and corrosion especially for those front exposed bullets but I'm down to whatsit 40 now as Contralube now is so expensive because one of the ingredients is now more expensive than, is it gold(?).

The wires, even unseen under the insulation sleeving, (is that the correct term(?)) can get crudded-up (now I know that's a "technical" term).
Nigel Atkins

Not a fan of W**0. For corrosion protection I like Fospro or ACF50. Even vaseline is better on the electric knitting. Personally I use Scotchkote but I admit it's a bit extreme.
Greybeard

Oh no, I didn't mean WD40!

I meant er, Servisol (the name I couldn't remember) now Super 10, I'm sure I used to use Servisol 40-something.

I liked the Contralube 770 if Maplins are really selling it for 45p a packet I'll have 10.

WD40 has taken over the world, the power of advertising, so much so that I don't readily see PlusGas around now (for a good penetrating/releasing fluid). WD40 also now sell 3-in-One products (well since 1995 it turns out, I'm slow to catch up and notice).
Nigel Atkins

Gday Oggers
IIRC If it is the same switch as the later marks then I think you can pull it apart and clean it etc as I did on my 1500 rebuild. I did this to fix a problem with the blinker action which was very stiff, a new detent spring and silicon grease (non-conductive) in the mechanism fixed it. Whilst apart I cleaned the dipper contacts and greased them, they being in good nick, not burnt etc.
If yours are damaged then its a real faff to repair but possible. New switches are apparently not much chop according to posts on this site. However, fitting relays to a new switch would probably give a good result. IMHO relays are absolutely essential whatever switch you use, then you can use Halogens, LEDs etc without an issue.
All advice on cleaning connections etc is spot on do this before you do anything else, who knows it may be a bad earth. I had to replace all the earth wires to the headlight/park fittings as the wire had gone black, whilst at it I duplicated the earth wire fitting one to each side (see pic, the screw is the new earth connection to the RH headlight and park lights)
Cheers
Rod



R W Bowers

Gday Oggers
PIC 2 shows my relay layout, the device on the LH side with the heavy red wires is the 40amp circuit breaker on the supply side in lieu of a fuse. If you are fitting relays do the horn as well, mine also has an electric fan
HTH
Cheers
Rod


R W Bowers

Rod
The horn switch only puts an earth on to the horn terminal, the other terminal has a positive supply all the time. So how do you wire up a relay with that system.
I ask because I can only use one of my twin horns, if I wire up both, they will only work when the battery is at a very high charge. (ie when the engine is running and nothing else is switched on). A relay may help.

Dave
Dave Barrow

Dave,
if you want relays that's fine but it sounds like you have an electrical problem that might be more than just the horns (or perhaps one of your horns is faulty but that doesn't sound right).

I'll leave it to Rod and others as I'd have to start at the battery andr wiring and then probably get lost.
Nigel Atkins

Oggers,
are you now able to fully display?
Nigel Atkins

Hi Oggers,


As you have no blue high beam warning lamp, the power is not flowing into the circuit.


Get a wander lead off the live side of the battery long enough to reach to the column stalk connector. Jump current into the Blue/white circuit, if it all comes to life, the column switch is faulty.

Think about fitting relays into the circuit if you replace the column stalk as the ones available now aren't that well made and would benefit from not taking the headlamp loads.


Regards Steve
fjxooiidlo

My money's on the column stalk. From what others have said it sounds like the aftermarket ones are crap.
Bill Bretherton

Afternoon Oggers.

What Steve said..... It all makes perfect sense. (Edit: also what Bill said).
I've been looking around in a desultory fashion and it seems that NOS switches of some types are still to be had now and then. Perversely it's the very late one that is unobtainable - it was only used for one year of production as I know to my cost since I had a hell of a task getting a replacement for mine. So much so that I fixed my original while I waited and passed on the replacement to another member of the bbs with the same problem.
The factory changed switches from time to time, but the only significant differences were whether or not it included the horn push and the style of connecting plug. Other than that it's more or less one size fits all and changing the plug over is a ten minute cut and shut job - easy because the wiring colour codes didn't change.
If you can't get NOS and you don't fancy a Chinese copy email Andy Jennings

mg@andyjennings.co.uk

He sells used ones at £12 a pop and is one of the most helpful people in the business. Either way relays are the way ahead. Even an old and worn switch should outlast you and me if all it's doing is clicking relays on and off.
Greybeard

Dave B, regarding your horns. There's a good chance you can adjust the problem away. There's lots of stuff on the net about this - here's a link to one discussion that might help.

http://www.mgexp.com/phorum/read.php?1,2266227

I imagine it's a problem with the sensitivity of the horn, possibly from a bit of corrosion inside it. So tweaking the adjustment might free things up and allow the diaphragm to oscillate.

As to the relay question just use the horn wiring to power the relay primary (the coil) and wire the earth from the horns via the relay secondary contacts.
The switch and relay neither know nor care about the polarity and will switch 12v or 0v just as happily.
Greybeard

Greybeard.
Thanks for the reply, the horns are new, and each will work by itself, they just wont work together, so it seems to be a power problem.
I don't see how you can put a relay primary contact on the supply side, as that line is always live, so the relay would always be on. Perhaps I am missing something.

Dave
Dave Barrow

On second thoughts, perhaps its ok to have a relay always switched on when the ignition is on.


Dave
Dave Barrow

You're right Dave it's a permanent live but the contacts won't close and make the secondary circuit until you earth it using the horn push connected to pin 85. As long as you use pin 87 (normally open) and not 87A (normally closed) for the feed to the horns.

I have no idea why the horns are wired the way they are, requiring a switched earth. If there is an advantage I don't know what it is. Anyone...?

Edit: crossed in the mail with your last post. Soz.


Greybeard

New made column stalk switches (some/all?) might be OK.

Now you know I'm the first to moan about modern parts quality but I have say (so far) the column stalk switch I bought about two and a half years ago and fitted September last year has been fine and feels solid whilst switching.

I got it from Bay Boy Classics IIRC.

The column stalk switch I bought for my GT6 about 11-12 years ago was just how Guy describes and needed attention straight after initial fitting, I've no idea if it's still on the car now or how long it lasted.
Nigel Atkins

Nigel thanks for the positive about Bad Boy Classics. I've bought a few bits from them and my experience of them as a supplier is very positive too.

Dave B - re: your new horns: the diagrams I have show the (optional) second horn wired in parallel to the first. Has someone by any chance wired yours in series? Not saying there's a stuff-up in the wiring, but it seems to me they might behave as you describe if that has happened.

BTW apologies to you Oggers for the thread hijack. How did it work out with the lights?
Greybeard

Grey,
I've only had a couple or few items from BBC but they've been good and the buying prices good, I'm not into their bling stuff but a lot of people are.
Nigel Atkins

used these folks before for electrical bits..
just putting it out there

www.autoelectricalspares.co.uk
Dave

David Cox

Greybeard
Thanks for diagram, horns are wired in parallel, I will have to sit down with a pen and paper and draw myself a circuit. I always find that's the best way to sort out electrics.

Dave
Dave Barrow

Gday Dave, the stalk switch earth is connected to the relay earth. Yes the relay is "connected" all the time and is switched by the column switch.
My horns were totally stuffed, two salvaged items from an old Datsun now work well.
R W Bowers

Thanks Rod, I understand it a bit better now.

Dave
Dave Barrow

Grey at al

Splendid stuff these forums....Update is that the blue indictor light now comes on when column stalk is pushed forward...I eventually traced it to a bad connection at the live contact of the lamp. I guess this means the switch at the stalk works? I will still try the double connection swap to verify, but as aforestated, I assume the issue is now between that connection and the headlamps.
Oggers

Well done on finding it.

Clean, secure and protect all the connections you come across or touch.

Unfortunately Maplins don't have there 45p packets but I've just sent off for some Contralube 770 before it all disappears, I recommend the use of something particularly to those exposed bullet connections.

https://www.12voltplanet.co.uk/contralube-770-electrical-contact-protector-8g-sachet.html

Nigel Atkins

Very well done indeed Oggers. Tiny faults like that are a bugger to find.

* I guess this means the switch at the stalk works? *

Yes it does, at least well enough to light up the high beam warning lamp, which is connected to exactly the same contact as the high beam supply itself. But... it's still possible for the stalk switch to be dodgy if the resistance is high enough to pull the voltage below the threshold for the lights, which need way more current. The good news is that the switch will certainly be man enough to switch relays though,if you decide to use them.

Don't forget to check the headlight bulbs themselves mate. If one pops it can sometimes cause enough of a "spike" to zap the other so it is possible that that could be the trouble. Simple stuff first, I firmly believe.

Looks like you're on a roll... there goes the weekend haha!
Greybeard

Just check that high beam works on both the selected beam setting and also on the momentary headlight flash with the stalk. Both obviously feed the warning light and main bulbs via the same blue/white wire, but via different contacts in the stalk switch.
GuyW

Are you sure Guy? I thought they're the same contacts but actuated two ways - a momentary cam and a latching cam. That said you're right it's good to check both ways.

Now I wish I still had a spare switch so I could watch it happening. Hmm.
Greybeard

Going from memory, and not intending to dismantle the column flasher switch to check! So not sure at all!
GuyW

This thread was discussed between 07/12/2017 and 15/12/2017

MG Midget and Sprite Technical index

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