Hello,

I have a 97 4.6 F150 with 189K on it. I recently replaced the PCM on the truck as it was having trouble starting in humid and wet weather. Now the truck starts great but the gauges on the instrument cluster seem to be going haywire. First the oil pressure gauge worked then it started jumping around so I replaced oil pressure sensor but no luck. Now it is the coolant temperature that is going haywire. It is low at one moment and then spikes up and then pegs out for the trip till I restart the truck. I have replaced that as well to no avail. It almost as if the coolant temperature gauge and oil pressure gauge move exact opposite from each other. The truck starts and runs fine so I think the issue is electronic. Has anyone experienced this before or is this an ECU (box behind the fuses inside the cab) or grounding issue? If it is a ground issue does anyone know where the grounding point for the cluster would be.

BTW, I have pulled the cluster and cleaned the contacts but no luck as of yet.

Sometimes the fuel gauge jumps around some and the battery gauge always reads high.

Any help would be great.

Thanks,
Jon

 

You still have a basic cluster issue when many indicators are unstable.
Good luck..

 

Have your battery and alt checked out.