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MG MGB Technical - Low/high beam switch

Does anyone have any experience changing the low/high beam/direction indicator/flasher switch on a '72 MGB? Specifically, is it necessary to remove the steering wheel and drop the column to replace the unit? Thanks. -Chris
C.E. Sampson

Chris,

Yes, you can replace it without having to remove the steering wheel or drop the column. The hardest part is getting the plastic covers back on when you are finished without scratching anything. You cuss for a while, realizing all along that some how they came off. It is really not that bad.

I have done this several times in 1973 MGB.

Good luck.

Robert
Robert Browning

What's the problem in there? I had the high beam contacts generate so much heat that they melted the plastic they were riveted on to. A pretty poor design in rectrospect really, driving along with high beam on I could feel the heat coming throught the cover!

When it started to happen for the third time I wired a relay into the high beam / flash cct which wasn't as easy as I thought it would be due to the way they constructed the switch. Does anyone know of a modification of the circuit that I can compare my solution to? Curious to know if I missed the blindingly obvious solution!
Dave Smith

Dave,

Your issue is interesting and makes me think that there maybe other problems involved. I have never had any problem with my switch(s) getting hot like you described. I have however seen other case of switches over heating due to bad connections - especially bad or loose ground wires. Just this week I was working with a company on a big plastics forming machine and they fried three separate, 480 volt switches ($400 each) and it was due to a loose ground wire.

I know that when I rebuilt my dash and went through the entire wiring on my car, a long time British car friend told me to add additional ground wire connections every where I could, especially under the dash and at the head lights. When was the last time you checked the wires and cleaned the wiring connections at the headlights?

If there was a bad/dirty/loose connection, it can cause the weakest connection point to get hot and/or fail, and the switch would be a weak connection.

Just something to think about for what it is worth.

Robert
Robert Browning

Chris
As above - if the heads OR low beam draw too much current, the plastic probe which pushes the copper contacts into place will melt.

Head and low beam relays will prevent that - as will renewing the wiring from the headlamp bowl to the loom.

You can very easily repair the switch by drilling out the lever arm fulcrum and building up the 'probe' with twinpack glue.

My old girl is also getting on a bit so 'Bin there, done that, and got the teeshirt'.

Roger
RMW

Robert and Roger: Thanks for your input. I do have relays for the headlights as I have Wipacs. The switch was just defective - replaced it in about an hour.
C.E. Sampson

This thread was discussed between 25/08/2005 and 26/08/2005

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