For 97' California F-Series and E-Series with Shunted glow plug relay. This allows you to replace the California wiring harness with a more available federal wiring harness. Adds the extra 3 wires to make the PCM properly communicate with the glow plug relay.
Install video link https://youtu.be/nwtf9rzWw-c?si=Wc5hAE0WcGkTy0h4