I have a 1980 W150 Power Wagon. I drive it daily. The other day I went to start it. It would start then when I let off the key it would die.

I figured it was the ignition switch because that has always been the case in the past with other vehicles.
So... I got NEW ignition cylinder/key and ignition switch. I even installed a new starter relay since I was replacing things associated with starting.

After installing it all.... the same issue remains. The truck starts up fine but as soon as I let off the key it dies.

Does anyone know what the heck is wrong with my truck?!?!