89 K3500 wiring questions

[Rktman]

I'm chasing down a few wiring issues on my 89 K3500 big block (currently 366, was originally a 454).

Regarding the Fuel/Oil pressure switch, I don't see one on this swapped motor. The PO installed a single wire oil sending unit (I connected the tan wire to it). The other 2 wires in this loom are orange and pink/black stripe. When I first connected the battery, one of those wires was hot and shorting out. Its dead now so there is probably a fusible link to replace somewhere.
What should I do with those wires as there will not be a fuel/oil switch to connect them to?

The next issue is the power to the pink wire of the fuel pump plug near the tank. I'm only getting about 8.5 volts. I know it needs 12v. Is there something common to check next? All fuel pump wires were severed when PO installed the flatbed. I'll be replacing the pump and sending unit.

 

[Rktman]

I'm chasing down a few wiring issues on my 89 K3500 big block (currently 366, was originally a 454).

Regarding the Fuel/Oil pressure switch, I don't see one on this swapped motor. The PO installed a single wire oil sending unit (I connected the tan wire to it). The other 2 wires in this loom are orange and pink/black stripe. When I first connected the battery, one of those wires was hot and shorting out. Its dead now so there is probably a fusible link to replace somewhere.
What should I do with those wires as there will not be a fuel/oil switch to connect them to?

The next issue is the power to the pink wire of the fuel pump plug near the tank. I'm only getting about 8.5 volts. I know it needs 12v. Is there something common to check next? All fuel pump wires were severed when PO installed the flatbed. I'll be replacing the pump and sending unit.

Nevermind, I found that the tan/white is the power and pink is the gauge.

 

[Schurkey]

Why not put the correct oil pressure/fuel pump switch into that engine so the fuel pump works properly?

The oil pressure switch is a bypass for the fuel pump relay; if the relay fails the pump still runs if the engine has oil pressure.

The correct switch isn't that expensive--and the Treasure Yards are full of 'em.

When I got my truck, I needed to replace a long stretch of wire harness under the truck leading back to the tank sending unit/fuel pump. The wires were corroded--fuel gauge didn't work, and the pump didn't get enough power.