The other method I had was to take the multimeter, set to resistance and screw the test leads to the terminals, and adjust to 16 ohms with the compensation pot ( assuming the indicator was working) so that it would read correctly. Then start the engine and see if it ran up to operating temp in the first minute. Worked because the indicators were calibrated at a certain current from the TC for full scale and the TC was designed to work into a certain resistance. Cold junction compensation was done by setting the pointer to a hair right of zero. Only time you would find the sparkies calling you to a wiring fault, they could never figure how it worked without power, so I often was there replacing 2 pins and 2 sockets in the shell, the electricians doing the rest, but I had to do the 2 TC wires and have it signed off.
More important was the big red light that said vacuum low, as this was generated from a pressure bleed off via a venturi. No suck - no combustion pressure and you were losing the big fan keeping you cool.