Issue with 1992 V4 120HP evinrude

Trying to help my 82 year old pops out. He just had open heart surgery in June of this year. Prior to this he decided to take his 90HP Yamaha off his pontoon boat and install the V4 120HP. Well it's been almost a year and it is still sitting on the deck.I was able to remove the main wiring harness from the boat he removed the motor from. Problem is he had already began this and it was a complete mess. I was able to get it all out and reconnected and the motor fired right up. In running the wires the harness that goes to the control box at the consol had a 3 wire lead with a plug, it also had two "CUT " wires. Bare with me as i am a carpenter by trade and far from a mechanic. I tried to perform a forensic research on where " Pops " cut them from and it appears to be the power trim gauge (tilt Up/down) My question is it's two wires and i am not certain they both go to the gauge or only one? And if so what is the second wire too? I have been reading all the post's and the information here is truely amazing. trying to get this thing back in the water so i can spend some time on the water with "Pop's" fishing. 5 years ago he would of had it done but old age is creeping in.