1990 Ford Bronco 4.9L Thermactor Air Pump & Check Valve Location Diagram

This document is a Ford factory-style schematic illustration (figure ID A13526-A) showing the secondary air injection (Thermactor) system components on an inline six-cylinder EFI engine, consistent with the 4.9L engine in a 1990 Ford Bronco as claimed by the uploader. The line drawing depicts the engine from a three-quarter view with the intake manifold, throttle body, and accessory drive visible. Key emissions components are highlighted in red: the belt-driven air pump mounted low at the front of the engine, the combination air control valve mounted near the rear/side of the engine, and two check valves, one on a hose routed along the front/left of the engine and one at the upper right near the exhaust manifold connection. Air routing hoses are shaded in gray to show how pumped air travels from the air pump through the combination air control valve and check valves to the exhaust system. An arrow labeled 'FRONT OF ENGINE' establishes orientation. A reader can learn the physical locations of the air pump, combination air control valve, and both check valves, and how the secondary air hoses are routed between them, which is useful for diagnosing or replacing Thermactor/smog pump system components.