I have a 1990 F350 diesel truck that blows the fuel,oil & tach gauges. The period between blown fuses is getting shorter. Has anyone had this problem before? Where I should start to look? Thanks.

 

I start by looking right behind the fuse box, make sure none of the wires are bare/burnt.

Basically you'll need to follow the RED-YEL wire from fuse #18, from the fuse box to the instrument panel until you locate the short. It also supplies the warning chime module and low vac warning sw.