I have an F reg 2.5 petrol Ninety and neither my fuel or temperature gauges work - they show empty/cold permanently. I've been trawling the forums for weeks now trying everything suggested to no avail.

I don't have a voltage regulator for the gauges, nothing on the back of any of them, nothing attached to the rear LHS of the binnacle and nothing I can see in the depths. I've been over the wiring with a multimeter and I get power at the power (green) terminals on the gauges, wire is looped from one to the other, earth seems fine from the black daisychained onto the central screws, there is continuity from the senders to the sender terminals on the gauges and the fuel sender reads 8.4v at the gauge and is probably about 2/3 full so that seems right. I've checked power both sides of the fuse although that seemed superfluous given that there is power at the gauge.

The fuel sender is new, the fuel gauge is new (although I now believe there was nothing wrong with the old one) the fuel gauge goes to full when the sender wire is shorted to earth, so I believe it works. The temperature sender is new.

I have no idea what to do now - by my limited knowledge/logic it should work. I'd be very grateful for some help please. Thanks in advance.

I had a similar problem when the indicator switch was faulty and draining power, they work off the same fuse.

Try putting in a new earth for each guage. My temperature guage was always reading off the scale hot until I fitted a dedicated earth. Now it's fine.

Thanks both. I'll spend some more time looking at the earth. What was the solution to the indicator problem (and how did you diagnose it)?

When I indicated the readings on the temperature and fuel dials gradually dropped. When I cancelled the indicator the readings slowly recovered. Then the indicators stopped working and the gauges read zero. The relay was full of water so I replaced it. That didn't help. The fuse (3) was not seated properly but cleaning it and pushing it home didn't solve the problem. I fitted a new indicator switch. The indicators now work and so do the gauges. But it hasn't rained much since, fingers crossed.

Thanks, I think I can probably discount the indicator thing then. I've tried a direct earth to the battery and that doesn't work either.