Electric Cooling Fan Relay & Thermostat Wiring Diagram - Ford Bronco

This document is a hand-drawn wiring schematic (uploaded as "wirethis.jpg") showing how to wire an electric cooling fan with a relay and an adjustable thermostat controller. The diagram depicts a fan (upper left) wired through a relay, with a note stating "we discussed the grounding options for this relay, you will have to work that out on your end." A temperature probe (blue wire) connects to a thermostat module, which has a green "trigger" wire and a red "12v power" input. A three-position switch on the right offers "manual on" (green), "manual off" (black), and "auto thermo" (blue) modes, allowing the fan to be run manually or automatically via the thermostat. A 20-amp fuse is shown inline on the red power wire feeding the switch, with a callout explaining that "this post needs 12v power from either the battery or the fuse box. you decide how you want it." The battery and the vehicle's fuse box are drawn at the lower left as possible power sources. Wire colors used in the drawing include red (power), green (trigger/manual on), blue (temp probe/auto thermo), and black (grounds/manual off). The diagram gives an installer the basic circuit layout for an aftermarket electric fan conversion with manual and thermostatic control.