I put Autometer water gauge and ammeter in my car. Took it out for a test drive, the water gauge read zero and the ammeter was at 9. Drove for about half an hour, nothing changed, and then stopped to fill up the gas tank. Started the car back up and the water gauge went up to 195* and the ammeter went to 13.7 volts. Turned the lights on and the ammeter dipped just a bit (maybe 13.5?), turned them back off and ammeter went back to 13.7. Got home, turned the car off, started it back up and both gauges sat at zero. What's everyone's thoughts?

Edit: Started the car up to put it in the garage, ammeter went to 12 and stayed there, water gauge stayed at zero. Turned off the car in the garage, started it back up, same thing.

 

Sounds like a bad ground or V+ connection at the gauges.
I assume you mean a voltmeter and this is an electrical temp gauge.

 

Yes to both. I was thinking ground also, but I don't understand why sometimes the gauges work perfectly. I'll have to look very closely at the ground wires. They are both grounded to the same place.

 

Since it's both your temp and volt gauge I would also say you have a bad ground or grounds. Did you use Teflon tape on the temp sensor?

 

No, should I have?

 

No, Teflon tape sometimes will prevent a good connection. I'm going to change my assessment, is the power supply for both the temp and volt gauge connected to the same place? The reason I ask is because the ground on the temp gauge is the block and ground for the volt meter is the dash. So I'm assuming your picking up power at the same place.