If the button is not working, might be a vacuum line problem. Vacuum lines engage the 4x4, might need to check the lines to the 4x4 transfer case.
three hoses that run from the top of the tranny down around the tranny and then back up to the engine
Check for broken vacuum lines to the front axle shifter.
The actuator of the Dodge Ram 4x4 is located on the top of the front differential. Depending on the year, the actuator is either vacuum or manually operated.
Check the vacuum lines that run down to the front wheel hub bearings if they are good follow the vacuum lines up to the 4x4 vacuum solenoidon the firewall and check for a stuck vacuum valve
You can find a diagram for the vacuum system in a 1995 Blazer 4x4 will be located in the Blazer service manual. The manual can be purchased in most auto parts.
Defective modulator valve.
Normally the vacuum line from a brake booster goes to the intake manifold of a gasoline engine. Sometimes other lines will be tied in to feed vacuum to cruise control pots or 4x4 actuators, but the main hose will be larger.
Vehicles made in the USA have a diagram on a sticker located under the hood in the engine compartment. The sticker shows the routing of the emission related vacuum lines. Vacuum lines ae connected to the inlet manifold at one end, to work on the depression at this point. There are several ancilliaries that may work off this, the most popular being the brake servo. Also sensors for the ignition (advance and retard), vacuum servos for 4x4 control, computer management box and emmision controls.
The 4x4 system on a 2003 is not vacuum controlled.
I need a vacuum routing for a 1995dodge ram 4x4 5.9L
Look for a broken vacuum line coming out near the ac lines on the passenger side under the hood.Look for a broken vacuum line coming out near the ac lines on the passenger side under the hood.