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MG MGB Technical - Tacho stops with headlights on

Hi,
My tacho in my 1969 MGB stops working when I put my headlights on. Can someone help
me with this problem
thanks
Alex
Alex

Check the earth (ground) connection to the tacho. It sounds like it might be earthing through the panel lights, which it can’t do when the lights are on.
Dave O'Neill 2

Yep, concur with that. Should be a black wire with a through-hole tag under one of the two knurled nuts that clamp the tach in the dash. UK tin dash anyway.
paulh4

Lots of these odd electrical issues are down to faulty or missing earth/ground connections.
On UK gauges there is a "daisy chain) of earths to all the gauge clamps which goes to ground on the body.
Allan Reeling

This thread was discussed between 08/08/2020 and 09/08/2020

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