H3 acuator motor
 

Anyone have info on changing the motor that controlls the 4 high lock in and out? And anyway to test it?

Unclip electrical connector. Two bolts, remove them, remove the actuator (#12). Pull the T Case seal (#11), put in fresh seal, re-install new actuator with the two bolts.
http://parts.nalleygmc.com/images/pa...14TX04-305.JPG

You can test for power at the truck side connector, some have had corroded connectors, frayed or broken wires give them problems.

A squared shaft comes out of the T Case through the seal and goes into the actuator. All the actuator does is turn the shaft to shift. If they get real wet.... like when you get stuck in deep water and muck for 15 minutes +.... they puke.

Yep just what he posted.
Chris

H3 acuator motor
 

Thanks Doc