Electrical problems

I never disconnected anything inside the truck. Only the outside. I pulled fuses and when I pulled IGN A which is a large 40a fuse everything stopped. I replaced and pulled smaller fuses. Eng E, ECM 1, ENG 1 were the 3 that stopped everything. I replaced all other fuses except the 3 and no flashing or noises. I put just 1 of them in and something acts out. It may be the interior lights, fuel pump relay clicking or doors clicking. I disconnected 2 ground straps from the frame (one below the heated core hoses on pass firewall, other on rear pass head). The one on the thermostat and one I'm not familiar with that is on a harness that's been looped (from the rear firewall) I left the other at the fuel tank and the 2 at bottom front of motor that contain the battery and another ground. I don't have the rear bumped and lights on yet not the front. I have wire brushes and sanded all the bolts and connecting point along with the connectors. Those are the outside grounds I have. Truck was running fine before the swap.
One other thing. I don't understand I believe G119. In one spot it says near thermostat housing on same page it says on front of block. I know both spots. Is the engine whole engine referred to as G119?

Do you have a diagram that shows illustrationto where these grounds are located? I found a ground on the side of the e-brake pedal but I dont think this is the G202 you are referring to.

Okay. I'm in luck. I just found the tech service manual for my truck. Omg the pages. I have found one problem. I will include a pic. It is of G103 and G150. I cannot find any reference to what G150 is.

I found g202. Inspected the connection and the wires. Everything looks good. G150 on the other had. No luck. There is no reference to where it is coming from in the Chevrolet workshop book I have. Still have the major electrical problem. Could it be that I don't have enough grounds and that when I turn the key or supply power its making the system act out?

I got figured out my short problem. It was a white wire that I grounded to the rear frame. Problem solved. Now the new problem is. It will start and run but shuts off almost immediately. Like I turned the switch off. The security light does come on but goes right back off after about 5 or so seconds. I put a jumper from 30 to 87 on fuel relay and pump does run and will start the truck but still shuts off. I tapped a jumper on the oil press sending unit connector and I do here it click on. My thinking is that something isn't telling the injectors to pull the fuel. Oh, fuel pressure is 65 psi and strong. Even when cranking it only drops maybe 2-3 psi. So I have a start but not staying running condition.