Horn stays on when battery is connected

SOURCE: I had my 2006 V6

try using the key to lock and unlock the door this should turn off the alarm also try pushing the unlock button on the remote, there are two horns a high and a low the are right behind the grill and if you want you can unplug them until you get the battery charged, but you will still have to turn off the alarm before the car will start.....GOOD LUCK

SOURCE: 2000 Honda Odyssey. The passenger side

The driver's Multiplex Control System is a small computer that controls (among many other things) the dash lights brightness, ignition key interlock, shift interlock, and has a tie in to the brake light system and horn relay. It may be that this small computer malfunctioned and started the whole problem chain.

However, I note from the factory shop manual that if polarity is reversed on the shift interlock--it can be damaged. Reverse polarity will ruin the diode inside the shift interlock. This could have happened when you jumped the battery--a brief period of getting the cables and terminals mixed up could have done it.

Checking the shift lock solenoid can be done by removing the steering column upper cover. Disconnect the shift lock solenoid connector (2 terminals). Using long jumper wires, apply battery voltage to terminal 1 (yellow wire side) of the solenoid and ground terminal 2 (green wire side). Check that the shift lever can now be moved out of Park. NOTE: applying voltage in the opposite direction of that above will damage the diode in the solenoid and will probably ruin it. Remove your jumpers and shift back to park and check that the solenoid locks. If the solenoid does not work properly, it will need to be replaced. This involves removing the end of the transmission shift cable and is a complex job. Remember, no power to the solenoid equals a locked solenoid--it takes power to unlock it.

The Multiplex Control Unit has a self diagnostic feature which checks the computer itself and inputs to the computer. The computer check is called mode 1 and the input test is mode 2. The diagnostic trouble codes are outputted to the ignition key light and beeper.

To test, first confirm that all fuses are good, especially fuse 9 (10A) in the driver's under dash fuse box (left kick panel) and fuse 13 (7.5A) in the passenger's under dash fuse box (right kick panel). Then use a jumper wire (a wire with small alligator clips on each end works best) to jump the two leads of the multiplex test connector. (This is a light green 2 terminal connector dangling from the same wire bundle as the brake pedal switch connector.) Buckle the driver's seat belt (avoids nuisance beeps). Now turn the ignition switch to on. After about 5 seconds, the ignition key light should come on and the beeper should beep for 2 seconds then stop for .2 sec. then beep once for .2 seconds. This indicates that the system is in diagnostic mode 1.

If no diagnostic trouble codes (DTC's) are present, the key light and beeper will not blink/beep again. If there are codes: about one second after entering mode 1, the key light and beeper will indicate the DTC and repeat it every 3 seconds. If there are more than one, the system will indicate them in ascending order. The codes will be a light flash and beep so you will have to count the flashes/beeps to keep track. The codes range from 1 to 6. Code 3 (three flashes/beeps) indicates a problem with the multiplex control unit itself. Write back here for other codes or for questions about mode 2.

SOURCE: I have a 1994 Honda,

Well, in the front of the car, lower front bumper I mean where your lower vent grill are, there is this circle metaliic thing, probraly kinda rusted. That is the horn, and what you can do is disconnect the wiring harness there, if not, and you don't really need a horn anymore, you can just cut the wire.

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