My Dyane fuel gauge has stpped working. used a new sender to test the wiring but no joy so could be the wiring or the guage itself. How do I test the gauge which of the contacts does what any one know.
there is a Youtube but it doesn't show which contact to connect to.

I believe a common fault, is a bad earth from sender to chassis.

I think the colours are the same on all A-series:
Mauve-sleeved wire is live to the gauge.
Yellow-sleeved wire goes from gauge to sender (via joints at bulkhead and rear inner wing).
The live feed (mauve) to the gauge is fed via the 16amp fuse with the blue-sleeved wires and should be live when the ignition is on. If it is, then disconnect the yellow-sleeved wire from the gauge and replace it with a temporary wire to earth. The gauge should then read 'full'.
If it doesn't, then the fault lies within the gauge, (unusual).
If it does, the fault is in the remaining part of the circuit, via the sender, to earth. If this is the case, with the gauge re-connected, disconnect the yellow-sleeved connections on the bulkhead and run a temporary wire from the gauge-side of the joint, to earth.
If the gauge doesn't read full, then the fault is between the gauge and the bulkhead joint.
If it does read full, then re-connect and try the same at the next joint, by the left-hand inner wing to determine which side of that joint the fault lies.
If it's after that joint, the wire may have rubbed through on the rear arm or tyre. If not, check the earth from the sender to the chassis/body. Then all that's left is the sender (or connections directly to it), so tank out.