either your heater control valve is bad or you heater control switch on your dash is broken pull the knob of and see if it is cracked.
it could be your thermo stat
Is it the push button style climate control panel? If so I am having the same problem. I can not adjust where the air blows from because its not getting the signal from the buttons. Also the lights are not Illuminated and the rear defrost does not work.
Your climate control in your 1998 Ford E250 Cargo Van blows cold air when in heat position and sometimes it blows warm air when in the cold position?
Compressor not running? Check fuses, check switch
You should check the thermostat to see if it is operating corectly, or your system may need to be perged.
You may have a stopped up heater core, or it may be a faulty heater door or heater door control. Answer: Check coolant level. Replace thermostat. Check heater control cable, located under small cover above the the passenger floorboard, near the console.
Horn button is a momentary switch. Yours sounds stuck. Check the contacts. Once it grounds, the horn blows & sounds grounded.
Check your climate control switches, and vaccuum lines. If you have electronic climate control, you probably need to have it serviced. Quite often in Grand Am's 91-2002 have had minor problems with weak linkages within the housing and routing of the climate control rod's and lines.
Check the fuse first. If the fuse is good apply 12 volts directly to the horn. If it blows then the horn button on the steering wheel or wiring is defective. If not, the horn itself is defective.
The most common issue is the heater / climate control valve. This can usually be tested in dual mode and checking for change in air circulation.
This may be a cause... My wife's 95 contour had to have the vacuum temp settings control unit replace 2 times. If you are constantly changing settings it really blows the valves in the climate control center... Just a thought.
The Same Situation Just Happened To Myself; A few Months Ago. I Brought My Honda Accord Into A Car Shop Course, All Along I Knew It Was The Lack Of Coolant