Sounds to me as though there's a short to ground on the line between the instrument panel and the gauge sender unit on the tank.
The gauge is basically just an ammeter. The sender unit in the tank is a variable resistor, presenting a high resistance when the fuel level is low, and a low resistance when the level is high. If the wire between the gauge and the tank is broken and just left "floating" it would show as empty permanently, if however it is shorted to ground (the car's body in this case), it will bypass the sender entirely and show as full.
Afraid I don't know where that wiring is routed in the AX, but working on intuition alone, I'd probably start at the tank end, especially where the wiring passes through the bodywork into the main loom. Had it fail there many years ago on a Metro anyway!
Current fleet:
07 Volvo V70 SE D5, 85 Sinclair C5, 84 Trabant 601S, 73 AC Model 70, 62 Rover 110.
Dash pod out on to the main dash harness
Connectors at the n/s A pillar
A grey ribbon cable that runs under the carpet
splits off near the rear seats
through a grommet (i think) and then along the top of the tank
2006 C5 HDi 170
1998 Xantia Activa S1
1971 D Special
2018 Renault Zoe,
are you the person sent me an inquiry regarding the AX tank sender i have listed on ebay, if so the one in your last photo looks the same type as the one i have for sale
current ride a BX 1.7 TZD estate
1986 MK1 BX 1.9na D Auto(in Mothman Andy's stable )
layed up roppy 1.9TD XANT estate, now gone to meet her maker
purple and lilac metalic 2CV(VIOLET)registered to her in doors
1972 DS special been layed up aprox 31 years
citronut wrote:are you the person sent me an inquiry regarding the AX tank sender i have listed on ebay, if so the one in your last photo looks the same type as the one i have for sale
