Techincall questions.. im a supra NOOb

[f00g00]

A clunk when you put it in drive means that one or more U Joints have gone. They are still there just the little pins have worn out. Be careful though as Ive had my universals changed before and the shop that did the work claims they put it together right and the driveshaft vibrated even after turning it one quarter turn till it was back around again. There are no machine shops here that can balance a driveshaft so Im on my third used one. The first one got screwed when the shop changed the center bearing and one of the yokes.
As for the horn see if its the one thats mounted on the firewall behind the cruise control.Thats the one thats tied into the alarm. I don't beleive the ignition switch is tied into the system except for getting disabled for cranking but you never know, just see which horn it is and disconnect it on the firewall if thats the one honking and you will still have your regular horn. The door locks are the ones that usually go bad for the alarm system.

[milkduds45]

Do you have an alarm on it. If so could be your alarm system. Mine has an alarm and when set the horn blows non stop no matter how you open car. Only goes off once key is in ignition and switched on.