2000 silverado, remote start

will it crank when you remote start it with the key in the ignition? did you actually follow the program instructions for the 555L or did you just hook it up and start the truck thinking it would program automatically? its been a while but i think you just need to hold the small button on the 555L until it starts flashing and then start with the key and let it run. as far as tach, you just need to find the the right wire and then start the truck while holding the valet button and let it run for a few seconds. you should also check to make sure to have both of the ignition wires powered, they are pink, and white at the ignition harness. you should power both orange and brown accessory wires too but i think only the orange is necessary for remote start. why do you have your status output going to both the 555L and the alarm? it only needs to go to the 555L it will do nothing for the alarm. and when you say "negative trigger" do you mean the blue status output wire?