MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - More electrical drama

Greetings,
I have a small but annoying problem with lights. Car in question is 1970 UK spec Roadster with the hi-lo beam control on the indicator stalk. All lights work except when I move the indicator to turn to the right or move from lo beam to high. In both situations the headlights go off completely for a moment and once indicator stalk fully in the desired turn or hi beam postion the lights are on again. This is more than a little disconcerting so has anyone any ideas as to where to start looking for the problem??
Many thanks
Fay
F Cunningham

first guess, dirty or bad contacts within the switch.
glg

Dodgy switch. If you can't open it up and tighten up the contacts it is a (expensive) replacement. But first check the security of the wire terminations on the switch itself.
Paul Hunt

Thanks for the comments..nothing seems to be loose or dirty so the switch may be faulty, unfortunately it is relatively new and it was very expensive so I may just have to put up with the light disappearing on me.
Thanks again
F Cunningham

F:
There are contacts within the body of the switch, but they relatively exposed and not too difficult to deal with if you felt like trying to make the switch right. However, if you only recently purchased this switch, you might want to discuss the problem with the supplier and ask for a possible exchange.

Short of that, I have found that the current replacements are reasonably well made in terms of the mechanical and plastic bits, but I find the actual contact parts to be rather shoddily made and indifferently formed, meaning that many have to be reworked to get them to a state similar to the original intention. I had to "re-form" the contacts (simple leaf spring brass contact arms with dimple pads for actual contact) so that the dimples lined up to make good contact at the appropriate times. Some sort of misalignment may be the cause for your problems, maybe not. But my point is really that you might be able to get your switch to work by simply studying its motions and applying a pair of pointed pliers as necessary to bring things back to where they belong to work as they should.

Given my experience with my "new" switch, I chose to install relays for the headlamp circuits so as to take the current loads out of the switch (I did not trust it to hold up for long under Halogen loads). This seems to have been a good move as the reconstituted switch has since served me for quite a few years now. FWIW.
Bob Muenchausen

I had a similar problem with 73 MGB. We tried a “new” switch and found that it made it worse. I have learned since then that while most of the new switches are expensive, they are of a very
poor quality. We found that by rebuilding the old switch, or a used switch, solved the problem. The switches come apart very easily and if you use a small wire brush on a Dremel, you can get to all the contacts. My switches and lights work great now.
Robert Browning

To what Robert says, I would add that most anything that comes in a generic white box these days is up for scrutiny. I have had good luck with genuine Lucas replacements, but inconsistent luck with most generic items.

The indicator stalk I reconfigured above was mechanically probably as good as the OEM unit. But the maker simply wasn't able to get the contacts bent into the right shape to do the job correctly. In both Robert's and my cases, a simple Quality Control check of the switch's functioning could have told the manufacturer which were good and which had problems long before they ever shipped them to a supplier. However, it appears that something that simple is not something they do, or at least do very well, for whatever reasons.

I have also wondered if there aren't really two markets for aftermarket parts. Those that a supplier requires under contract to have a certain max. failure rate, and then a second market which consists of the packaging and selling off of the duds from production to other, less caring suppliers. That is probably not true, but one has to wonder sometimes.
Bob Muenchausen

I have had bad luck with almost everything sold 'aftermarket' including this extremely expensive new switch. It is frustrating to buy these parts and then have them either not fitting or lasting only a couple of months. Unfortunately here in New Zealand there is little choice and I don't have access to the vast array of outlets that the Northern Hemisphere has..the ironic thing about this switch is that I only brought it to replace the original as I got fed up with having to resolder the indicator wire on all the time and gave the original away to some one in the UK off this board..wishing I hadn't now).
Anyway thank you for the advice to fiddle with the contacts..I did (albeit with no knowledge of what I was doing) and it seems to be working OK again now.
Thanks again
Fay
F Cunningham

This thread was discussed between 26/05/2003 and 31/05/2003

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.