Had my HFCM replaced 2 weeks ago. Was under truck today, and noticed orange electrical plug just hanging right below HFCM? It comes from the same wiring harness where other plugs are plugged in into the HFCM? Do you guys know where this plug is supposed to go? I never saw it before, and I am affraid that they forgot to connect it somwhere to HFCM... i tried to look, but could not see where it could have been pluged.
2003 Ford Excursion Limited, 6.0 Powerstroke, 4x4, V&B code springs, bilstein shocks.
I can answer it very easily. That plug would be for the fuel heater that was deleted on 2006 and up model years. This question is the exact reason why I always replace the harness too on 2005 and older models (6C3Z-9F759-A). The reason Ford deleted the fuel heater on replacement HFCMs is because it was felt that compression pressure heated the fuel sufficiently enough. The fuel heater was also causing corrosion inside to housing too, which inevitably lead to other problems.