Auto Meter Oil and Water temp gauge

[dojo]

New build, new gauges, new Ron Francis wiring. We have good power to the gauge feed into these 2 gauges, but, at the sending units on the manifold, we have a very weak light on our test light. We have good grounds, actually all the gauges are grounded in the same place. Fuel gauge is working, volt gauge working, but, water and oil pressure gauges are not working. Shouldn't we have 12 volts at the oil and water sending units also?? Help...

[ray_mcavoy]

Originally Posted by dojo

Shouldn't we have 12 volts at the oil and water sending units also??

No, that's perfectly normal for your test light to be dim when connected to the sending unit wires of either the water temp or oil pressure gauges. That's due to the internal resistance of the coils inside the meter. In fact, having a full 12V present on the sending unit wire can potentially damage the sending unit.

Originally Posted by dojo

We have good grounds, actually all the gauges are grounded in the same place.

What is the location of your ground point?

The sending units ground via their threaded connections into the engine. So for proper operation, you need to have a good ground connection from the engine to the GND terminal on the back of the Autometer gauge.