So I'm Having Clicking Going In Dash an At Passenger Side Box an Can Hear It At Transfer Case. But Lights Flickering an Then They All Go Out an Blazer Won't Go Forward or Backwards. But If I Shut It Off an Start Back Up an Immediately Go In Drive or Reverse It'll Move Then More Clicking an Lights Flash an Its Like Vehicle Is In Neutral (It Just Rolls) Even In Park. Shut It Off an Back On Again It Was Like It Registered It Was In Park. When This Occurred The Other Day I Managed To Get It Back Home From Neighbors House But Felt Like It Was In 4Lo. I Replaced Box On Passenger Side Thinking Lack Of Communication Between Box An Transfer Case Cause Couple Times Light Would Just Flash or Go Out Completely But Tapped The Box an Lights Would B Fine Again For Days an Even Weeks At A Time. I've Tried Turning Key Forward an Back 5 Times an It Still Clicking an Flashing Lights Even Before Starting an Even When It Starts Up. I'm Stumped

 

It Is A 2000 Chevy Blazer With The 4 Button 4x4 System

 

Any previous work with 4x4 system done?

the system uses vacuum lines to operate, the first place I would check is the vacuum switch near the firewall in the middle above the distributor. There should be two lines going into it.

You said you are able to start the truck when drive is selected? “Shut It Off a Back On Again It Was Like It Registered It Was In Park.”

I would also check things like linkages under the truck, the cable should be secured and if it is not it can get stuck

 

I've Replace Control Box On Passenger Side Firewall Vacuum Actuator Under Battery an Transfer Case Itself So Far

 

So I've Just Got Done Doing Vacuum Actuator Under Battery an Started It Up. Lights Flashed an Still Hear Clicking an Then All The Lights Went Out Again an Service 4 Wheel Drive Light Came On

 

could be encoder motor issue - service light however I believe is related to fluid level - I didn't get a service light when I had vacuum line blown off causing it to not come out of 4x4 high