on my 1989 mustang 2.3l the temp guage will only work after you turn the key back after the engine was on.(the temp guage rises after the engine is off).any know why this is or what it could be?
Have you looked at any of the wiring connected to the coolant temp. sending unit? Sometimes shorts have this effect on the gauge. Also check all fuses.
It could be the sending unit itself is toast.
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