Rapidtrent
Member
So, I got my '71 Hemi Challenger out of hibernation (Climate and Critter Controlled) only to find that the Oil Pressure Gauge wasn't registering. The engine sounded normal, but I wasn't about to take chances. Back in the day - my attention would be given to the Oil Pressure Sending Unit as they are prone to failure and well this one might be 55 yrs old so. But in my mind, there were other possibilities including wiring, gauge failure, fuse or an engine mechanical despite no tattle-tail sounds. Process of elimination; My good friend Blair, who runs one of the top tier Mopar restoration shops on the East Coast suggested that I test the wiring before going all-in on a Sending Unit replacement. This was brilliant advice. I disconnected the OPSU connector and ran a test light (for resistance) to the negative terminal. Turning the ignition key to run (not start) the gauge came to life! This eliminated any wiring or fuse (are they fused or just fusible linked) possibilities. My focus shifted to the OPSU which I tried to resurrect by cleaning and tightening the contacts and threads to enable grounding (even through the Teflon tape). But to no avail unfortunately, the old unit had given up the ghost. Upon replacement and starting, the dash gauge came to life (again) reading close to the "H" while warming up. Interesting observation, the test light was blinking while I was conducting the wiring test. Not a continuous light as I expected. Unfortunately, I can't upload the short video I made. Here's a couple of Pics. Next Project - Fuel Gauge!
