* Vacuum Solenoid: This is the primary actuator. It's usually located on the firewall or near the engine, and is electrically controlled by the transfer case selector. It's the component that actually routes the vacuum based on the 4x4 mode selected.
* Vacuum Lines: These rubber hoses run from the vacuum solenoid to the transfer case actuator. They're essential and a leak in these lines will cause 4x4 problems.
* Transfer Case Actuator (or shift motor): This is the component *on* the transfer case itself. It's a diaphragm that mechanically shifts the transfer case based on the vacuum signal.
To find the relevant components, you'll need to start by tracing the vacuum lines. Follow the lines from the transfer case actuator (located on the transfer case itself, usually somewhat towards the rear and underside). This will lead you to the vacuum solenoid.
Important Note: Because there isn't a single "switch", diagnosing 4x4 issues requires systematically checking the whole vacuum system. A malfunctioning vacuum solenoid is a common culprit, but broken vacuum lines or a faulty actuator are also possibilities. A vacuum gauge can be useful to test the system's vacuum integrity.
Consult a repair manual specific to your 1995 Chevy Blazer S10 V6 for diagrams and further guidance. This will provide much more precise locations and troubleshooting information than a general description.
