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Fuel gauge

Posted: Thu Jul 02, 2026 4:27 pm
by Blaketon
Does anyone know or can people check how many amps their fuel gauges consume? There has apparently been an issue with some replacement voltage stabilisers getting hot when used in Minors.

I have a standard late fuel gauge and a Mini temp gauge (Like the ones found in some Minis up to around 1980, which shared a Minor style speedo) and found that the fuel gauge circuit was consuming roughly 1.2 amps and the temp gauge roughly 0.4 amps. It's the fuel gauge that's the issue.

Re: Fuel gauge

Posted: Thu Jul 02, 2026 4:45 pm
by svenedin
I have a late car with late fuel gauge and I have the original Smiths thermal instrument voltage stabiliser. These work via a bimetallic strip that gets hot via a heating wire and "chops" the battery voltage to around 10 volts for the instruments. Due to how they work, they do get hot. I might have time to look for you tomorrow. I am assuming I would have to disconnect the connections to the fuel gauge and place the multimeter in series in the circuit to measure the current?

Stephen


PS: You can sometimes find NOS Smiths instrument voltage stabilisers. Part number BR 1309

Re: Fuel gauge

Posted: Thu Jul 02, 2026 5:00 pm
by Blaketon
Many thanks. I put the ammeter between the outlet of the voltage stabiliser and the wire to the gauge.

Re: Fuel gauge

Posted: Thu Jul 02, 2026 6:52 pm
by oliver90owner
One thing for certain - it will only be milliamps, rather than Amps.🙂 Moving coil meters only draw microamps, before being shunted to suit the range required.