Just sold a 94 just like your truck with a dump box.
It was DOA and had a bunch of wiring issues...
Ended up having a questionable pump as well,once hot it would not restart.
The new Owner is a 6.5 fan and was told of the issue, i threw in a used pump with the deal.
The original plan for the truck fell through and then the New owner inquired about it...Sold
A extension harness and new PMD will cure the no start issue with any luck
90 Chev 3500 c/c 4x4,6.2na,400 auto,4:10 gears.DSG Timing gears,main girdle, isspro tach, pyro,boost,oil and trany temp.Dual Tstats, High volume peninsular pump,on shelf, Custom turbo and intercooler 85%complete. Change of plans for the dually, it's going to get a Cummins. Both trucks are Blue 90 4x4 crews