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The VIN won't help me but it might at the dealer's parts department. It is real common for Ford to make mid-model-year changes, which is why there's often multiple wiring diagrams and optional parts choices. The most important piece of information when visiting the dealer is the vehicle's production date. On cars that is found on the driver's door sticker. If you don't find it there on your truck, look in the glove box.
I'm using a different source for a wiring diagram this time. This one shows two versions, ... One without cruise control, and two slip rings, and one with cruise control and three slip rings. There's no mention I can find here of a clock spring. To add to the confusion, the ground circuit common to both systems goes through one of the slip rings, but there is no color shown for that wire. It appears the ground connection is right on the steering column. Thinking back to a mid '70s Chrysler product I had that developed a dead horn, the steering column was attached to the dash with two bolts that went through a pair of nylon isolators. Those prevented squeaking while allowing the column to move under extreme temperature changes, but it eliminated the ground connection. There was a "W"-shaped strip of metal sandwiched into one of those spacers to make the ground connection. Cleaning that strip and repositioning it solved the dead horn issue. You might want to check for that, or check for voltage on a paint-free point on the column when you press the horn button. The meter's ground test lead must be on the body, not the steering column.
If it does appear a slip ring is causing the problem, look for the dark blue wire going up the column. Grounding that wire should turn on the horn relay.
Speaking of that relay, while studying this diagram, I confirmed all the cruise control functions except "On" come through their own circuit and slip ring, but that circuit gets 12 volts from the "On" switch that comes through the horn relay. When things that look silly like that are done, it's because you might never notice the horn is dead until it's too late, but you are more likely to notice the dead cruise control. Repairing the dead cruise control with a new relay would fix the horn too, before you even knew it wasn't working. You might want to visit a salvage yard first for a replacement relay and try that.
Tuesday, January 2nd, 2018 AT 4:30 PM
