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MG MGB Technical - Head lights tail lights and side makers not workin

Hi

I have a 1978 MGB the tail lights side markers and low beams do not work I bought a new switch for the column and that did not fix it the high beams work but will not stay on any help would be greatly appreciated

Thanks Ryan
Ryan Brehm

Were they working and stopped? Or is the car new to you and they have never worked in your ownership? In the latter case it could be multiple problems.

When you say the high beams work do you mean from the main lighting switch or only from the headlamp flasher? If only from the flasher then that uses a different supply. If the front pilot lights don't work either then it probably has to be the main lighting switch, or the voltage supply to it on the brown wire. How about the panel lights? Is the switch sub-harness fully pushed into the connector on the main harness?

You should be able to pull the switch forwards without pulling the wires off, so use a voltmeter to test for voltage on the brown wire. Whilst you can get the wires on the wrong spades with the lamp logo facing you and the switch lever pushed away from you all three terminals should be connected together so all lights should work then if not in other positions. In the middle position brown and red should be connected together

If the main beam works off the main lighting switch then it will be a problem round the dip switch which is causing the dipped beam problem, plus perhaps the top two fuses in the fusebox affecting the rear and front pilot lights.

But you say 'side marker', is this American spec? How the switch fits may be different on those but electrically they are the same, and the side markers should come on in the first position of the lighting switch with the rear lights and front pilot lights.
paulh4

This thread was discussed on 07/02/2024

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