Symptom Chart

WARNING: This page is about a different car, the 2006 Ford F550 Super Duty, 2006 Ford F450 Super Duty, and 2006 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

SYMPTOM CHART

Condition	Possible Sources	Action
No communication with the vehicle security module	Circuitry Vehicle security module	REFER to MULTIFUNCTION ELECTRONIC MODULES .
The horn is inoperative	Fuse Circuitry Horn Clockspring Horn switch Central junction box (CJB) Vehicle security module	GO to PINPOINT TEST A .
The horn is always on	Circuitry Clockspring Horn switch Central junction box (CJB) Vehicle security module	GO to PINPOINT TEST B .