Was driving my freshly "put together" 76 280Z (w/ 77 motor) around and I saw my temp gauge die out of nowhere. I checked the bullet connector at the sender (it was connected still), cleaned it up and can't get the reading back to the gauge still.
I've read from other threads that a bad voltage regulator can cause this and oil pressure gauge to not function. My oil pressure gauge works fine.
The sender and sensor are new, and coolant level is high enough. I'm no electrical guru, but I turned the key on and checked the voltage on the sender wire and grounded it and I get these pulse voltages of around 10 volts every second on my meter (0 to 10 consistently). I don't know if this is a check from the ECU.
With not knowing what to make of the readings off the sender wire, I thought about the sensor or sender being bad. My idle at cold start is around 1200rpm, and as I drive the car around it slowly climbs up to 1800-1900rpm. Does this correlate with a faulty coolant system - heat -> resistance -> increase idle? I may be jumping to conclusions from this gauge going out but I'm pretty new to this and trying to understand related systems before yanking stuff and replacing new (my previous and expensive habit). If there are any tests anyone can recommend, I would appreciate it.