2000 gmc w4500 box truck

i think i might of posted this in the wrong spot on the wire diagram request so i copy it here. please delete which one is the wrong place this is the tilt cab same as the isuzu NPR HD i put a remote start and alarm on my truck, no wire diagrams to be found or bought! it was time to do it old school and find them all with my multimeter only lol. i got all the wires on the ignition wired, hot, access, start, ign 1, ign2. it will start but when remote start a throtle cable in the engine keeps going in and out and the truck revs then almost dies over and over. when the key is used that cable does not move! there are 2 wires left on the ignition. 1 of them is always a ground key on and off. the other one i believe is my issue. when the key is off its 12v , when key is on its ground! when remote started it jumps from 12v to ground over and over as the truck revs then almost dies. so what i believe has to be done is make this wire ground when the remote start is on, but i have never saw a wire that was hot and i need to ground it b4 so this is what i was hoping someone else has dealt with

Could be keysense? 12v at rest ground when key is inserted? I am not familiar with Izuzu/gm systems, but alot of "american" cars do need keysense or strange things can occur. When in doubt duplicate everything the key does!