1990 Ford Bronco 4.9L Thermactor Air System Diagram - Air Pump, Bypass & Check Valve

This document is a black-and-white line-art schematic (Ford illustration number A13527-A) showing the secondary air injection (Thermactor) system components on an inline six-cylinder engine, uploaded as applying to a 1990 Ford Bronco 4.9L with automatic transmission. The isometric drawing depicts the engine's exhaust manifold and intake plumbing viewed from the side, with an arrow indicating the direction of the FRONT OF ENGINE. Three components are called out with labeled arrows: the AIR BYPASS VALVE, mounted high on the engine near the rear with hoses routed to it; the belt-driven AIR PUMP, shown mounted low at the front of the engine with its pulley visible; and the CHECK VALVE, drawn separately at the left with its inlet tube and hose clamp. A reader can use this diagram to identify the location and appearance of the air pump, air bypass valve, and check valve, and to understand the hose routing between the air pump, bypass valve, and the air distribution tube along the exhaust manifold. The drawing contains no torque specifications, part numbers (other than the illustration code), or written procedures — it is purely a component-location and identification diagram.