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MG MGB Technical - Yet another Electrical crapout

Hello All,

Only yesterday did I do my first ever proper repair to my 68B of 3 months. (that was a 2x6v to 1x12v battery conversion).

Well fixing that gave me the grand (yet stupid) idea of starting to work on other things I wanted to do.

Well, I had decided as everyone does, that the dash lights were not bright enough so following the myriad of wonderful advice on here and the archives, I bypassed my dimmer thing and removed the tacho and cleaned it and painted the inside with hi gloss paint.

The reason I did only one guage was to see the difference. Planned to do the others afterwards. Well after doing just the one, WOW, it makes a HUGE difference. I can actually read the thing now at night without having to squint or guess that the needle is around about in that vecinity of the guage.

(Please excuse my spelling and/or grammer but it is 1:00am and I am REALLY tired)

Anyhow, after doing this I went for a spin around the block to see how it looked in pitch black and as I made my last turn home, the indicators dicided not to work.

Further check also showed that the high beam wasn't working either. However I know that they were working after everything I did because I was using all these things just minutes before.

The Flash thing works (this had been moved from the footwell to the stalk by the PO) so I can pull back on the stalk and get the full four filaments light up and if I swear profusely and wiggle the stalk, I get a flash of high beam for just an instant, can't tell however if it all four filaments lighting up or just the highs. The high beam light in the speedo only turns on when I get either the wiggle flash happen or if I pull back the stalk to get the normal flash.

All other lights and things are working fine, all the dash lights, wipers, horn etc.

I have checked ALL the connections I can find with relation to the stalk on the steering column and indicators and headlight wiring and I cannot find anything that is not FULLY connected or loose. The grounds are all OK as well.

I pulled the stalk off the steering column to check the contacts in there and everything looks fine. But 'surprise' the screw mounts that hold the clamp thing to the stalk around the steering column broke while trying to put it back on.

So what I now have is a car with a bright tacho, no high beams or indicators and a dangling stalk.

BTW, my car is green. I spose that could probably explain it but I don't have any bolts with the paint off.

PS- Also got a sore back and cramped up hands from doing all this in the HUGE under dash area that I am sure was assembled by Oompa Lumpas.

Thankyou in advance for the help.


Ad.
AJ Hooker

AJ

STOP FIDDLING--------If it ain't broke, LEAVE IT ALONE.
Bumpkin

Well I'm running low on enthusiasm now.

I managed to fix the stalk but still have no indicators or highs.

:-(

Guess I'll just have to keep swearing at it.
AJ Hooker

Just noticed that fuel gauge ain't workin either.
AJ Hooker

Your swearing and wiggling getting them to flash momentarily indicates that it is the switch contacts that are at fault, it uses the same wiring for flash as main beam so it won't be that.

Seeing as it is the same stalk the internals could have failed altogether hence the indicators not working, if you don't get any glow from the dash tell-tale either. At least you only have to buy one switch to fix both things :o) but it is pricey :o(

If the tach works but the fuel gauge doesn't the problem is either in the voltage stabiliser, gauge, tank sender or the wiring and connections between them. With the ignition on briefly ground the green/black at the tank, and if the gauge starts rising smartly to F disconnect it, the problem is either in the sender or the tank ground. If connecting the tank ground (black) and green/black together does the same thing it is the sender, if not it is the tank ground. In my experience (four senders now) they work normally when the fuel level is above a certain point but drop to below E below it, flickering on and off (if you see what I mean) for a while as the level sloshes about that point.

"Oompa Lumpas" ? No - Uncle Lucas.
Paul Hunt

And it continues..........

I have cleaned all the contact points, switched, fuse wiring etc.

Now I have indicators but stil no high beams. Also the fuel gauge is working again.

However.

The horn isn't working now as well.

Only thing I can think of now is to buy a REALLY bright torch to use for high beam and just yell 'honk' loudly for the horn.
AJ Hooker

Do the interior lights work but go out when you press the horn button? If so the bottom fuse or connections to/from it are bad. If neither work at all then recheck that fuse and its connections. If the interior lights work all the time measure the voltage on the horn purple and purple/black as you operate and release the horn button. If the voltage on the purple dips from 12v to significantly less there is a bad connection back towards the fusebox. If that stays at 12v and so does the voltage on the purple/black then there is a disconnection back towards the horn button. If the voltage on the purple/black drops but not all the way to zero there is a bad connection back towards the horn button. Deal with these last two by checking the multi-plugs under the steering column are pushed fully home, and all the pins, and the button itself. Sometimes the column ground can be high-resistance, there is no grounding cable as such, you could try fitting one but I used a relay as I had high-resistance connections inside the (motolita) wheel button as well.
Paul Hunt

Thanks Paul,

The only interior lights I have are in the gauges and they are all fine with the headlights on low/high and flash.

I'll try out your suggestions this afternoon and hopefull will fix everything this weekend.

I shall let you know how it goes.


Ad
AJ Hooker

AJ
Ignore advice not to fiddle. Fiddle away! Half the joy of owning an MGB is the ability to stand back after you've fixed the problem, and claim (in Sir Edmond Hillary-esque) I finally knocked the bastard off!

My advice: Nut it out (and Paul's just 100%A1 in terms of technical advice), get it working, then stand back, curse it, and bask in the afterglow of success! You've just beaten LUCAS, Prince of Darkness!

Good on yer mate.
Ray
R P Shoebridge

Thanks,

I did ignore the advice not to fiddle.

If I didn't want to fiddle, I would not have bought an MG.

Well anyway, I have tracked everything down to a dodge stalk. Everything tests as it should but the horn and highs isn't working. Also the stalk body is getting damn hot. Took it for a 10 minute drive then touched the stalk body (thing all the contacts are sitting in) and nearly burnt my hand.

So the stalk is shot and I need a new one.

I also thought I would test yelling 'honk' from the car with the top down as the horn isn't working and from the stares I got. I think it is effective.

hehehehe

Just dor safety's sake, I have disconnected the battery till I can track down a stalk.

I don't spose anyone here knows of the part number? It is a 68B Mark I Roadster.


Cheers All,


Ad
AJ Hooker

Have a look at http://www.ukmgparts.com/index1.html?o=105369760232147 and click on the MGB/GT/V8 link and then switches and horns. All the part numbers are there.

HTH
Iain
I D Cameron

Hi

As for the high beams and the horn I would check the wiring connections where the connections are made inside the front wings, on both sides, in the front. I am not a big believer in the connection sytem Lucas uses namely the "bullets and tube" style. They seem to corrode easily. I have replaced these type of connections where I could, on my B by cutting them off and soldering the wires together, then heat shrink to seal the new connections now, no problems. FWIW Alan
Alan

A very hot switch implies a short to ground somewhere on the load side. Investigate that before replacing the switch, or you may well burn out that one as well.

Bullets and connectors are perfectly adequate, but after 30 years the bullets may need cleaning and the connectors replacing.
Paul Hunt

This thread was discussed between 17/02/2004 and 20/02/2004

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