Fuel gauge faulty with side lamps on

[JOWETTJAVELIN]

The needle on my fuel gauge has begun to go down to half full when the side lamps are switched on; the tank itself is full and shows full with no lights on. This is something I have never noticed before. 1956 car. Can anyone please help?

[bmcecosse]

Probably poor earthing on the side lights.

[JOWETTJAVELIN]

Thanks I will have a look, it has been going along a lot of muddy tracks recently.

[beero]

Possibly poor earthing on the speedo. The fuel gauge and the speedo illumination are both earthed through the 2 screws on the side of the speedo.

[JOWETTJAVELIN]

Thanks chaps, 'twas indeed a poor earth (to the speedo).