Gauge testing/Voltage regulator issue

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May 1, 2026 | 12:10 PM

Aidanlockett1

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4wd High

Joined: Nov 2025

Posts: 9

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Gauge testing/Voltage regulator issue

Hi everyone, I’ve been trying to figure out this issue since I bought my truck. The gauges (minus tach and spedo) are all kinda funky. When warm the oil pressure goes to completely low when I drop below 1k rpms but goes back to normal when I give it gas. I did the oil pressure gauge mod and it did no change to this behavior. My coolant temp also consistently reads low despite the cooling system being brand new, radiator, thermostat, etc…. Fuel gauge also never read right and when wiring an aux gauge to try and get accurate readings I noticed I was getting 8v or ~78 ohms resistance FROM the gauge itself. Which the sender was within spec by 10ohms when full but when connected to the gauge itself, it read differently. Volt meter is pretty bouncy whenever I use the window regulators or any electrically significant items.

I had to rebuild my alternator with a victory lap kit because the brushes were toasted and it wasn’t charging. I replace the voltage regulator inside the alternator but I’m worried it was a dead unit or not functioning properly. I’ve read I need 5v at the gauge, not 8. Any further testing that I can accomplish would be helpful to know.

i also thought it might be the gauge itself that is starting to go bad due to age, but I’m not positive. Thanks for the help..