How do i replace the vent actuator on a 2002 gmc envoy?

SOURCE: replace starter on 2002 GMC Envoy SLT

check to see if the starter itself is getting a signal to crank. youll need to use a test light and have someone else try to start the vehicle, while you probe the wire to the starter to see if it is getting power. if not, check the starter fuse to make sure its not blown, as well as the starter relay to make sure that is good too (very common on gm's for bad relays) if the fuse and relay are good, but your not getting signal, it is an ignition switch problem.

SOURCE: 2002 GMC Envoy

If your 2002 gmc envoy or sierra will not even turn over with a kown good battery try starting it in nuetral then go back to park and try starting again. There is a park nuetral safety switch that can malfunction. Turn the key on then shift into nuetral, then turn fully to start.
 

SOURCE: Replace the thermostat on 2002 GMC Envoy

4.2L Engine the thermostat and the neck where the hose goes on is one unit $25 at autozone

1. Remove the necessary coolant from the radiator.
2. Remove the alternator, Loosen the outlet hose clamp at the thermostat housing. Remove the outlet hose from the thermostat housing.
3. Remove the thermostat housing bolts.
4. Remove the thermostat housing from the engine block.
5. Clean all of the surfaces of the thermostat housing.
6. Clean the sealing surface of the engine block.

SOURCE: Need firing order diagram for 2002 gmc envoy

one, five, three, six, two, four

The plastic intake should have this sequence molded into it somewhere, and even the corresponding cylinder numbers in front of their respective holes. Have fun, and thanks for posting on Fixya.com

SOURCE: 2002 gmc envoy shuts off when i turn on the ac whil ideling

If it does it when idling I would suspect an IAC motor (Idle Air Control). If it is opening too slowly the added air the motor needs will not be supplied fast enough and the engine will kill.

It could be other things also but this is where I would start.