Pyrometer gauge flickers

[65-f100]

Just installed my pillar and Autometer gauges. They look great but I'm having problems with the pyrometer power wiring. I've tried 3 different 12V source wires. The gauge flickers with electrical loads. If I turn the high beams and my driving/fog lights on - it kills the pyrometer altogether Turn the fog lights off and it reads normal. I also notice fluctuations with turn signals, etc. Anybody have a known good 12V source that won't have the interference problems? Thanks!

[john8662]

I suspect a grounding problem, run a direct ground wire from one of the batteries into the cab and connect it to the same place you found your ground source when wiring your gauges.

I grounded my gauges under the dash on a bolt for the dash, it already had another ground wire going to it.