* The brake booster: This is a large canister usually near the firewall. It has a fairly thick hose connecting to the intake manifold.
* The distributor (if equipped with vacuum advance): A smaller hose connects to the distributor.
* The carburetor (if equipped): Several hoses connect to the carburetor for various functions, including controlling the fuel-air mixture. This is more likely on earlier models or specific engine choices.
* Emissions control components: Various vacuum-operated devices for emission control (EGR valve, etc.) will have hoses connected.
* HVAC system (Heater, AC): Vacuum can control the HVAC system's operation in some configurations.
To find the vacuum hoses you need to locate these components and trace the hoses connected to them. A repair manual specific to your 1989 Ford Ranger's engine (e.g., 2.3L, 2.9L, 3.0L V6) will show you a diagram of the vacuum system. You can usually find these manuals online or at auto parts stores. Looking at a diagram is crucial; tracing them visually is not always reliable.
Without knowing what system you're working on (brakes, emissions, etc.), or what's malfunctioning, it's impossible to point to a specific hose.
