engine and drivetrain Instrument Ground Tip

[ingraham]

Here is a very simple fix for some gauge problems. Remove the nut and washer(s) from the back of the fuel and temp gauges, and add a #8 internal tooth lockwasher to each. This lockwasher should go against the printed circuit board (PCB), followed by the original washer and nut.

This fix accomplishes the same thing as adding ground wires from those gauge studs to the car body, but it's simpler.

Background: Both the fuel and temperature gauges in my '72 tii were reading too high. Often they were OK with the engine cold, then pegged with the engine warmed up. I spent quite a lot of diagnostic time isolating the problem, because I wanted to know exactly where the bad connection had developed. In my case, the gauge ground stud was losing contact with the trace on the PCB, even though the nut was tight. I verified earlier that the other ground connections (battery to engine block, battery to body, fuel level sender to body, and instrument cluster to body) were good.

[Tiger75]

I had a similar problem. My temp guage was irratic. It would jump around and then settle down. When I would turn on the aux fan, the tempt gague would read higher than before. I added a groud wire from battery to each gauge as covered in FAQ. It did not solve my problem. Finally, I added a ground wire from the battery to the altenator and that was the fix that solved my problem.

[fmtrxr1]

Thanks for the tip on installing the washers to the back of the gauges. This worked like a champ.

[ingraham]

I'm embarrased to report that the fix was short-lived for me. I'll know more next time I dig into it.