Gmc envoy, no crank, no start - GMC Cars & Trucks

I have changed the switch ? Which switch ? Ignition electrical switch or key and lock cylinder ? still want turn over? Won't turn over ? When you turn the key to start what happens ? Does the starter engage an spin the engine around or nothing happens ? Programming the key for the anti-theft system needs to be done if key and lock cylinder was done ? Do you know what happens when you turn the key to start ? I have changed the switch ? Which switch ? Ignition electrical switch or key and lock cylinder ? still want turn over? Won't turn over ? When you turn the key to start what happens ? Does the starter engage an spin the engine around or nothing happens ? Programming the key for the anti-theft system needs to be done if key and lock cylinder was done ? Do you know what happens when you turn the key to start ?

Circuit Description
Moving the ignition switch to the START position sends a 12 volt signal to the engine control module (ECM)/powertrain control module (PCM) Crank Request circuit. The ECM/PCM verifies that the transmission is in the PARK or NEUTRAL position. With the transmission in Park, voltage flows through the Park/Neutral position switch and feeds the starter relay coil. The ECM/PCM then grounds the control circuit of the starter relay. When the starter relay is energized it allows battery positive voltage to the starter solenoid S terminal. On some vehicles the starter will continue to crank the engine with the key released until it starts or the crank command has timed out to prevent excessive heat build up in the starter circuitry or the ECM/PCM receives an engine run flag.

Did you have the ECM programmed ? Circuit Description Moving the ignition switch to the START position sends a 12 volt signal to the engine control module (ECM)/powertrain control module (PCM) Crank Request circuit. The ECM/PCM verifies that the transmission is in the PARK or NEUTRAL position. With the transmission in Park, voltage flows through the Park/Neutral position switch and feeds the starter relay coil. The ECM/PCM then grounds the control circuit of the starter relay. When the starter relay is energized it allows battery positive voltage to the starter solenoid S terminal. On some vehicles the starter will continue to crank the engine with the key released until it starts or the crank command has timed out to prevent excessive heat build up in the starter circuitry or the ECM/PCM receives an engine run flag. Did you have the ECM programmed ?