1989 Chevy Cheyenne fuel pump

Electrical problem
1989 Chevy Cheyenne V8 Two Wheel Drive Automatic

Hi. My brother had a problem with his fuel pump. He installed a new on a few weeks ago and his truck ran fine. A few days ago he got in and started it, it ran for 15 seconds then killed. He turned the key off, the on and started the truck and it ran for15 seconds and then killed. That is all it will do. Yiu have to turn the key off then back on to get it to run for 15 seconds. The key does not have a chip in it. We tested the fuel pump relay and it is working. We installed a new fuel pump relay just in case and no change. Tested the wires going into the relay with key on and all were doing what they were supposed to as per haynes manual. The dark green wire that comes from the pcm has 12v to ground when the relay is unplugged. When I plug it in, and test the wire for power with a test light, I get nothing. Is that normal or is that the problem. Thanks for your help, Jimmy