Door Jamb Switch Wiring

[ncaaref]

Hi all need some help here. The truck is a 1985 GMC Sierra K1500 It cam with one factory door jamb switch and the light under the dash, that did not come on when the door opened. I am attempting to wire Dome lights inside the cab and add the other door jamb switch. I was able to get a wiring harness from an old truck that had 2 switches wired in with the light under the dash. I can figure out the wiring to save my life. I know it is something simple but I just can't wrap my head around where I am going wrong. Out of the fuse block I have a wire going directly to the drivers side jamb switch and then the other wire is to the ground. I have power going directly to the dash light from the fuse box. I can get it to work but only the drivers side jamb switch will work. Any help on how to wire this so that it will work with the factory lighting would be greatly appreciated.