GMC 3500 Vandura fuel pump ground issue

[CraigSmith1967]

I am having issues with the ground on my 1994 GMC Vandura box truck. Has a v6 in it. Fuel pump plug has power to it but it does not come on when I try to start the engine with the key. Headlights also aren't working. I am thinking it is a ground issue. I replaced the ground strap from the back of the engine to the body. I replaced the fuel pump and the fuel pump relay, as well as the oil pressure switch which activates the fuel pump on starting.

I can activate the fuel pump by jumping across two of the pins on the three pin plug for the oil pressure switch, so I know the pump is working and has power to it.

Is there a ground lug under the dash somewhere? Any other pointers on what it could be. GMC repair manual isn't much help since it's a box truck on a 3500 van frame/chassis.

Thanks.

Craig-