Hey guys. I got a 51 Ford F1, original gauges. 12V neg ground conversion, Runtzs on each gauge. Oil and gas work as normal. Temp gauge is acting weird, sit on full hot while ignition is off, goes to cold when ignition is on. Ground the sender post, nothing happens. Nothing changes with or without the sender(s) hooked up. I assume the gauge is bad but never had one go full on while off, anytime had a bad gauge it just didn't work. Just want to confirm I'm not missing anything before I go on a hunt for another gauge.