Why are my gauges erratic on my 77?
The gauges go to appropriate levels at starting, then - in unison - the temp, oil pressure and fuel level all slowly go to zero, then head back up some then head back down some, etc. If it weren't all three, I would think it was a sensor, but it sounds like ground to me. I have removed all three, unhooked all connections cleaned thoroughly with contact cleaner. No effect.
I think it may be a ground at,the guage cluster itself,or cluster is going bad.
I agree with your ground theory, but it may not be the cluster connections, there are grounds for the dash in three locations, right and left side where the dash lower mount attaches to the body will be some ground wires and then in the console area will be some more. Have you checked the relays, one could be weak and unlatching while driving.
Are these ground wires secured under bolts or are they in multi-pronged connectors?
They will be both on this year.
And the ones bolted to the body will be located?..... Thanks for your help, by the way.
On either side of the dash, where the lower dash brake attaches to the body.
just run a new ground wire from the body to the guages
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