2006 CHRYSLER VAN PUT KEY IN TO CRANK AND HORN BLOWS AND WILL NOT CRANK

Have you tried putting the key into the ignition switch and starting the car ?

In some vehicles, you can place key into driver door cylinder and manually lock / unlock which may turn horn off.

My info says the horn switch is molded into the airbag module. You can't service the horn switch separately. You would have to replace the air bag module, if the horn switch is the problem? Air-bags can be dangerous, safety is your responsibility.
The wire going to horn switch is a ground for horn relay, it might be possible to use external horn button to sound the horn. That probably isn't very professional. Be careful with air bag.

If the engine will not crank in park, will it crank in neutral ?
Have you checked for voltage at the starter when the key is in the crank position ?

how do I reset one of two keys that the unlock,lock,trunck does't work but the key turns the engine over.

the key sensor is bad

This is your security system. Your van thought it was being stolen. Next time do not leave your keys in the van and lock the doors.

Could be a short in the wire to the horn. I would inspect it under the hood. The horn has power even when the key is off, so a short could cause this. If it`s in the steering wheel, I would let a professional work on it, since working around the airbag sensors is dangerous.

http://www.edmunds.com/chrysler/townandcountry/2005/discussion.2.html

the lower half on the page on this link is good reading.
http://www.aa1car.com/library/tire_monitors.htm
wait a minute now I think I remember correctly!
I believe this is the way you do it on the chrysler 05:
have the key OFF place the tool (magnet) over the valve stem.
turn the key on (DONT CRANK IT!)..
seems like I remember that the van alarm then will beep letting you know its recognizing what you are trying to do. then remove the magnet. I "think" the van alarm will beep again but not sure.
I would have someone inside the vehicle looking at the display while you do this. it may display certain messages indicating the state of the function but I think it will be an audible beep from the horn .. this would be so the dealer could have just one man doing the job if you take it there.
I'm pretty sure I am right on this but I will do some more searching on the matter .

hoorn take the wire off hook another horn up see if it is the horn itself if not it is the horn relay or the horn button