07 tahoe, prestige aps997n remote start

eddie302-

  Have you confirmed the wiring with a volt meter?  I would remove the 6 pin ign connector from the remote start and check with a volt meter while turning the key to the acc, on, and start positions, and confirm the correct signals are present based on the remote start colors.  Also confirm the Brake and Hood signals/sense, as well as system ground.

If the correct signals are present, you need to confirm the tach connection and program the tach.   The unit will not start if the tach isn't programmed.  

Also, if you are using voltage sense, you will need to program the unit for voltage mode, then start the vehicle with a key at least 4 times to learn crank time before the unit will remote start.