Truck started doing this yesterday. Leave for lunch with a friend come back to office, shut truck off and the horn starts going off. Didn't touch the steering wheel or anything at all. Put key back in ignition turn key over and the horn stops. Got home last night pulled into garage and shut off truck, horn goes crazy, headlights won't turn off. Finally turned key back over and everything shut off. Sounds crazy and irritating to say the least. Anyone have any ideas or similar experiences. BTW keyless entry stopped working about 2-3 days ago also. Thanks in advance.

 

Was the horn going off like in alarm mode or just constantly? Maybe has something to do with the clicker? Just guessing here.

 

I just KNEW you had a 98 when I read the thread title. Might be a CTM issue.