Our 2001 Expy XLT has a factory installed alarm. Recently I installed a new horn assembly, the original had quite.

Now the horn honks 1 time approximately every 30 minutes.

Anyone have experience solving this issue?

Definitely cannot afford to take it to a garage anytime soon.

Thanks

 

Remove or disconnect the alarm... After all, it is 12-13 yrs old.
If that doesn't work, who needs a horn?

 

1) Did you replace the horn assembly with an aftermarket one, or Ford Parts?

2) Did you just unplug it and plug the new one in, or did you rewire/splice the new one in? (Connector C136, wires: BL and YE/LG)

3) Did you have to disconnect ANYTHING else while you removed the defective horn?

If it have sounds every 30m, I might suspect that's kind of a "Hey, I'm letting you know something is wrong", but I don't have the workshop manual in front of me to see what diagnostic info it offers.

 

Jymmm, thanks for your response. The answers to your questions are:

1) Did you replace the horn assembly with an aftermarket one, or Ford Parts?

Bought an new horn through our local Ford dealership.

2) Did you just unplug it and plug the new one in, or did you rewire/splice the new one in? (Connector C136, wires: BL and YE/LG)

I hooked a volt meter to the horn connections and had my wife press
on the horn section of the steering wheel. It reads good and the new
horn works great, except for the intermittent honk.

3) Did you have to disconnect ANYTHING else while you removed the defective horn?

Nothing else was disconnected.


If it have sounds every 30m, I might suspect that's kind of a "Hey, I'm letting you know something is wrong", but I don't have the workshop manual in front of me to see what diagnostic info it offers.

Yeah, I've thought the same but have not been able to figure it out.

Thanks for your response.


@ r2millers: The alarm system works fine. Go figure.

 

Are all the wires covered properly so they are not able to ground on anything.

 

xSgtRenegadex, I know the connections at the horn are good. I will go back and check the wiring leading back to the wiring harness for worn areas.

Thanks

 

Check your airbag system...

Turn your ignition to on, dont start the truck, see if your airbag light illuminates with the rest of the idiot lights. If not, then your problem could be in your airbag system.

 

Following up on the suggestion from xSgtRenegadex to check for a short, I checked the wiring harness to the horn and the wiring around the alarm control module under the dash.

While under the dash I thumped on the alarm Impact Sensor and noticed the led light on it flashed super fast. Remember the instructions for this sensor, I turned it's adjustment **** counter-clockwise to raise the sensitivity level.

Then I reached up to honk the horn and the horn did not honk. All I heard was a dull clicking each time I pressed the horn button.

After a few minutes of aggravation and a few minutes visiting with the 2 Mormon gentlemen that had stopped by, I decided to unplug the alarm Impact Sensor. Not the alarm control module, just the sensor.

The horn works. Honks when I hit the spots on the steering wheel. Honks when I lock the doors with the key fob. Honks wildly when I hit the alarm button on the key fob.

I may replace the Impact Sensor someday. And then . .

 

Glad you found a solution!

Funny thing, I can't find mention of an "impact sensor" in the wiring diagram manual.
Closest thing I can find is mention of "Perimeter anti-theft disable circuit" connector pinout.
Section: 117-4, Connector C257, pin 13 (BK).

When someone finds a solution, I try to look it up and learn from it.
I'm not saying you don't have an impact sensor, just that I couldn't find mention of it =)

Over the decades, I've been bit on the ASSets far too many times from Ford wiring.
Once it was a wire splice in the middle of the harness. It wasn't soldered or crimped, but they used pure compression (like in a vise) on the copper wires in an attempt to "fuse" them together and didn't even protect it from oxidation/corrosion.

 

This is a Ford Vehicle Security System, probably a special order add-on, post production.