I have a 2002 F-150 with 205,000 miles. Im experiencing problems with my cruise control and my horn. My cruise doesn't work at all. It hasn't worked for several months now. I got the recall done for the cruise deactivation switch but my cruise wasn't working for weeks before that. My horn behaves very strangely. It works only when the ignition is in the OFF position but when I press the horn my truck chimes as if my door is ajar. It does nothing when the ignition is on or when the truck is running. I've already changed the clock spring thinking that may have been the problem but it did not help. The horn also works fine when i lock my truck and with the panic mode. Ive checked both the horn fuze and relay and both are fine. Anyone have any suggestions???

 

Remove the passenger side foot well cover and inspect the grounding stud and wire connections for corrosion damage.

Your symptoms are of an open ground from the switch assembly in the steering wheel to chassis. Check the above ground connection first. After that, you'll need to break out the multi-meter for testing.

 

I've checked the grounding stud and all the wires for corrosion and it all seems fine. I forgot to mention that my horn began acting this way after driving through lots of water on flooded streets after a heavy rain. Im not sure if it's related but could the water have caused my problem?

 

PROBLEM RESOLVED...thanks to littlejudge! The problem was with the the cruise control unit located under the hood, in front of the fuse box. The electrical part of the unit had shorted out. When I removed the electrical plug I noticed two of the pins were fouled. After removing the electrical board from the mechanical unit, I could also see that there were several shorted connections. I went to the local junk yard and could not find a like truck but found a 2001 model taurus. The unit had Taurus/Sable 200 printed on it but when I looked over the circuitry, it looked identical to the one that came off of my truck, so I took the chance and got it anyways. When I got home and hooked it up, I got my horn working as well as my cruise. Im not sure why Ford has specific vehicles printed on these units but they seem to be identical. It cost me $18.
Note: I first removed a unit from a 1999 taurus and looked over the circuitry and noticed that it was not the same configuration. It looks the same from the exterior and would fit on the same, but I don't believe it would have worked.

 

The difference in the electronics is the tuning for throttle response, transmission kickdown, and power-to-weight ratio. You might notice the cruise is either sluggish, or surges. If so, keep looking for the right servo top; if not, just keep cruising!

 

Ok, thanks Steve83. I'm glad to know the difference. I have tried it a few times and it seems to be operating fine. I will keep an eye on it and see if it presents a problem. Thanks