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MG Midget and Sprite Technical - main beam not working

Just doing a pre MOT check and found main beams not working ,they work ok if you flash them but not when selected so wiring seems ok from switch and relay is working when flashing suspect the switch itself only 2 years old lucas switch .
mark heyworth

Wiring okay - check.
Relay okay - check.
Fuses (if fitted) okay - check.
Lamps okay - check.
Only leaves the stalk switch contacts. It's not uncommon I'm afraid.

If you're lucky you might be able to clean them up and maybe tweak the leaf spring to get tighter contact.
Greybeard

Except there is no relay. Adding a relay is often the best prevention to protect the delicate switch contacts and spring from failing due to overheating.

2 years was about the life span l got from replacement stalk type switches before l added lighting relays. They are poor quality compared to the Lucas originals which happily work for 40 years or more. Since then one of the same repro has lasted 7 years so far, and counting.
GuyW

Agreed with all Guy, except that Mark mentioned a relay.
It seems a bit of hard luck that the switch went wonky even with one fitted, which is why I speculate that a spot of TLC to the switchset might do the trick.
Greybeard

Sorry Grey, l missed that reference to a relay, though from the way it is worded it looks like Mark may have the 'flash' function connected via a relay, not necessarily the main lighting circuits. If that were possible?
GuyW

It's certainly possible, but more likely that the relay is being operated by both the dip switch and the flash switch - or not, as the case may be.

It does sound like the dip/main switch contacts, or a duff connection between switch and relay.

Time for a circuit tester or multimeter.
Dave O'Neill 2

Quite right Dave. There'll only be one high beam relay as there's only one conductor to the high beams. The stalk switchset has separate contacts for high beam and flash, but only because the two functions are in physically separate positions of the switch and one is latching, the other momentary.
Both contacts are connected to the same output wire, (blue/white) that goes to the high beams or relay primary as appropriate. So if there's a dud connection it will be in a very small area, in the switchset itself or in the multiway plug/socket combo right next to it.
Greybeard

took switch off and it was a damaged contact managed to fix it with a bit of solder all working fine now probable poor quality new lucas switch.
mark heyworth

Well done Mark.
Greybeard

<< probable poor quality new lucas switch >>
who'd have guessed ?
Dave
David Cox

This thread was discussed on 30/05/2018

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