I have a 87 chevy truck and the oil pressure gage pegs to the right
when I turn on the key.Number 6 wire on the gage harness is hot when
the switch is on and the other two post move the gage in either
direction when grounded,this truck is somewhat cobbled since the cab
was replaced with a 83 cab and the engine which runs fine is a 87 fuel
injected 350.I would like to know the technology behind how this gage
works,Thank you for any support you can give.