Latching Relay

Ground relay case and connect a jumper wire between pins one and two. Connect a 12 volt test light between pin three and ground. Apply voltage to pin two. Test light should not light. Momentarily short pin two and pin four.

Fig 1: Ford Motor Co. Heated Rear Window Latching Relay and Relay Circuit Test Connections

Courtesy of FORD MOTOR CO.

Test light should come on and stay on, even after short is removed. Relay is located under lower edge of instrument panel on left side.

Fig 2: Heated Rear Window Diagram F-100 - F-350 Series

Courtesy of FORD MOTOR CO.