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MG MGB Technical - No high beam

To all
Went out last night in the 1970 MGB to pick up take away Thia for dinner and found my high beam headlights do not work, symtom as follows
Normal beam works fine.
When pushing indicator stick foreward to engage high beam l have no head lights at all.
High beam indicator light does not come on.
I am mechanical not electrically orientated so please be gentle with your answers.
Where do I start ????
David Levy

If you pull the stalk towards you, do you get main beam and/or blue indicator light?
Dave O'Neill 2

Dave,
Thank you for your quick response.
When the indicator lever is pulled towards the driver both high beam and indicator work.
I guess I am looking at a faulty contact in the combination switch on the steering column.
David Levy

Correct.
paulh4

IMO the simple easy way to start (ell apart from getting the cowl on and off) is to disconnect the battery(s) live and earth connections (earth first and put back on last) get the cowling off and clean the stalk contacts with electrical contact cleaner and a small clean brush.

Don't go too overboard with the spray as it'll only drip off and be wasted but a little flush action can sometimes help. Whilst clean try to operate the stalk in all its directions to clean and prevent you possibly moving crud from one area to another.

Wait for everything to be dry, should be a matter of a second if your not gone overboard as the electrical contact cleaner evaporates to air, then loosely replace cowling, reconnect battery(s) and see if it's worked.

Sometimes just repeatedly moving the stalk (or switch) many times through its positions can in itself clean up contacts (again you'd want the battery disconnected).

For items you may not use a lot it's best to test or use those items to test them, get them moving or working and keep the contacts clean, like the horns, wipers, heater blower, hazards and perhaps headlight main beam/flash.


Nigel Atkins

No need to disconnect the battery, just leave the lighting switch off, and remove the purple fuse if you are bothered about the headlamp flasher circuit being live.

It's more likely to be maladjusted/broken contacts or a broken wire than just dirty contacts, so close inspection first to see what is or isn't happening as you move the stalk.

A UK 1970 should have the plastic switch, first image shows it in the dip position and 2nd in main beam. The dip contact is on the other side, this side shows the main beam and flash contacts. Look just to the left of the purple wire and you can see the different positions of the moving contact. For flash that contact moves all the way down to the lower contact. More pictures at http://www.mgb-stuff.org.uk/dip.htm#1






paulh4

Yes a good look-see is always a good idea and with the info Paul has given you know more what to look for.

Disconnecting the battery(s) was to allow David perhaps not being confident with electricity and for possibly PO wiring and/or alterations which may be poor quality or not follow factory wiring or standards.

Whatever the problem actually is I'm still for cleaning of all the connections and switches within the stalk including indicators as fluff, grit or crud could be around the mechanisms and contacts and/or if you've got the cowling off do it now.

Nigel Atkins

To all,
Thank you for all the good advice.
I now have a job for the weekend. It will be interesting when I remove the cowling to see what has happened to the elastic band that I put on to help the blinker cancelling mechanism. I might find it jammed in the high beam contact area.
David Levy

Had the same problem with a replacement indicator switch, but I built up the cam.
paulh4

Update
Thanks to Paul's description and pictures I was able to locate the broken contact.
Next question
Has anyone had experience with the after market brand "Classic Gold" switch from Moss ($50 + shipping) as compared to origional Lucus part from E-Bay ($118 delivered)
I have always believed that you get what you paid for and am leaning towards the Lucus part.
Originality is not a big concern.
David Levy

Moss Classic Gold parts are supposed to be higher quality, and I've always found them to be very good to deal with on the few occasions I've had a problem. What's the shipping cost?

Unless the eBay item is NOS (and one would hope it is for that price) it's going to be an unknown quantity.
paulh4

This thread was discussed between 11/10/2020 and 16/10/2020

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