Nick - there aren't any fuses, hidden or not, that would have any effect on the starter or the gauges, and likely the reason the truck won't start [assuming the new starter does turn it over] is the ignition circuits are in a similar condition to the starter .... you might start by going over
all the wiring and connections [
especially any grounds] under the hood, and check for moisture in the distributor and in the cap towers
what you should have learned is not to power wash electrical things - also note that with a power washer you likely blew water thru some of the holes in the firewall where there might be wires running that have frayed a bit over the years .... if you feel you need to clean the engine, do it not running with critical bits covered with plastic bags
Bill
