Having issues with 4WD. I have an electronic switch. When I turn the selector to 4 HI or 4 LO nothing happens. No clicking in the relays, nothing. I have changed the switch out. Checked appropriate fuses. Changed both solenoids. I have constant vacuum to both solenoids and through the vacuum line from the 2WD solenoid to the actuator on the front axle. I have 12 volts to both solenoids but I do not have ground from the GEM to the 4WD solenoid, only to the 2WD solenoid. I'm thinking I need to replace the GEM but want someone's more experienced opinion before I tear into the dash and pull the GEM. Your help is greatly appreciated.

 

Have you watched this video? It might help.