Electric Fan Thermostat & Relay Wiring Diagram - Manual/Auto Switch, 20A Fuse

This document is a hand-drawn wiring schematic (uploaded as 'wirethis2.jpg') showing how to wire an electric cooling fan with an adjustable thermostat controller and a manual override switch. The diagram shows an electric fan connected through a relay, with a temperature probe feeding a thermostat unit that provides a 'trigger' signal (green wire) to the relay. The thermostat receives 12v power (red wire). A three-position switch offers 'manual on', 'manual off', and 'auto thermo' modes, allowing the driver to force the fan on, force it off, or let the thermostat control it automatically. Power is routed through a 20a fuse from the fuse box. A note instructs the installer to 'wire it to a keyed circuit,' warning that if wired directly to the battery, the fan will continue to run after the motor is turned off. Another callout notes that grounding options for the relay were discussed separately and must be worked out by the installer. Wire colors depicted include red (power), green (trigger), blue (temp probe/switch), and black (ground). This is a community-shared installation guide rather than a factory document, applicable to electric fan conversions such as on the uploader's 1979 Ford Bronco.