MGB Register Forum

The off side headlight on my '73 GT does not work. The lamp and the near side one are ok. Any suggestions?
Donald Carmichael

Presume both main and dip are affected. Check the connectors where the headlight wires are connected to the main harness (follow them back from the back of the light. Also check the earth is Ok.
It's worth removing the light assembly and checking there's power to the connector. I had a similar problem on my Land Rover except the light was very dim and this was caused by corrosion in the connector to the bulb. I used a electrical switch cleaning fluid to remove the corrosion.
Of course it could be the bulb but it's very unusual for both filaments to fail together.
Hope this helps.
. Vic Butler

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I absolutely concur with Vic but would add the following - 60's/70's wiring harness commonly use bullet type in line connectors which often fail due to corrosion. They can be resurrected by prising them apart, lightly abrading the connecting parts and reassembling and protecting with silicon grease/Vaseline or similar. On your model there is a "nest" of these connectors just under the fuse box and indeed the lucar connectors on the box and the starter relay also fall foul of corrosion and poor connectivity.
To be fair though, unless your car has been rewired, the harness is now 43 years old and some folks consider treating all connectors as service items which need periodic cleaning and protection or even replacement.

Thanks for these replies.
When the garage gets a bit warmer after this cold snap I will revisit this.
Donald