Hello, I have a 2000 GMC Sonoma (4.3 Vortec) and I’ve been trying to engage it in 4wd but when I’m in neutral and I click the 4hi, 4lo or even 2hi nothing happens, not even a flash, I’ve checked fuses and connections and nothing seems to look bad, fuses are fine, kinda stuck.

 

Just had the same problem. I replaced the TCCM (transfer case control module).. Put in a Dorman brand. Solved that problem. Now having problem with the actuator. Replacing this weekend. TCCM controls the actuator depending on which button you select ie: 2hi-4hi-4lo-Auto 4WD. TCCM is under dash and actuator is underneath by transmission/transfer case. Hope this helps..