I've gone through the Cornwall A7 site diagnosis. I have got good earth to central pole, and supply from fused source. The gauge immediately flicks to full when ignition turned on.
When the tank (rheostat) wire is removed, no change.
Oddly, I've swapped the gauge with another and... it does exactly the same.
This suggests that either BOTH gauges are faulty - or something else!
My question - how do I check or fix the gauge itself. It seems to be dismantle-able... but not sure how.
original gauge...
24 ohms T terminal to earth
42 ohms supply terminal to earth
and the other gauge is the same... hmmm
one is a x42139 8HP 6V "petrol" marked
other x49522/S "Fuel" marked
When the tank (rheostat) wire is removed, no change.
Oddly, I've swapped the gauge with another and... it does exactly the same.
This suggests that either BOTH gauges are faulty - or something else!
My question - how do I check or fix the gauge itself. It seems to be dismantle-able... but not sure how.
original gauge...
24 ohms T terminal to earth
42 ohms supply terminal to earth
and the other gauge is the same... hmmm
one is a x42139 8HP 6V "petrol" marked
other x49522/S "Fuel" marked