2000 tahoe horn honks when driver door is open with key. Keyless entry is not working.

To arm content theft alarm.
1. Open the door.
2. Lock the door with the power door lock switch or
the remote keyless entry transmitter. The
SECURITY light should flash.
3. Close all doors. The SECURITY light should go off
after approximately 30 seconds. The alarm is not
armed until the SECURITY light goes off.

If a locked door is opened without the key or the remote keyless entry transmitter, the alarm will go off. The headlamps and parking lamps will flash for two minutes, and the horn will sound for 30 seconds, then will turn off to save the battery power.

Unlock all doors, foot on brake, all doors closed. Cycle key quickly but carefully on-off appr 10 times until the car honks one time.

Do not turn the key far enough to start the car, just to the 'on' position so the dashboard lights up.

When the horn honks, open and close the driver's door, press any remote button and that's it.

Program another remote? Quickly open and close the driver's door again and push a button on the 2nd remote. That's it.

When you're done, remove the key and the horn should honk 3 times. You're all set.
Sometime it takes more than 10 on-offs to set program mode. Open/close the door, lock/unlock etc, wait 10 minutes, then try again

If your vehicle is equipped with a factory keyless entry system and you have the owner's manual, there should be a section in the manual describing how to change your options with your system. But if you have an aftermarket system, which I am thinking this the case, you will have to manually go into your dash under your steering wheel and cut the wire going to your horn from the security system. Once you have accessed your wiring underneath your steering wheel, there is a main harness with a bunch of wires going to the steering wheel. In this harness you will find a DARK GREEN/VIOLET small gauge wire and you should see another wire tapping into it probably coming from the security module. Just cut it off but leave the DARK GREEN/VIOLET untouched and this will eliminate the horn honks.

Tire pressure monitoring system. Start by checking your tire pressure and set to what the sticker on the drivers side door frame indicates. If this does not turn the light off you will have to re-learn the sensors to the vehicle. This is done by:
reset the tire pressure monitoring system, to do so, you need to get your key fob, and put your ignition key in the ignition, turn it to the accesories position, and simultaneously press the lock and unlock buttons on the key fob. hold them until the car honks the horn.

then take something to let out air in the tires, you need to start with the left front then go to the right front, then the right rear, then the left rear.

start at the left front, drop the pressure in the tire until the horn beeps, -usually takes 8 seconds or so. then repeat on the other tires in the order above.

After you finish with the final tire, the horn will honk again, then you know your done. usually honks 2 times.

and then you can turn the key off, and set your tire pressures.

look online or go to the dealer and find a reprogramming procedure.

Your lock settings were most probably changed from your remote unit. By pressing both lock and unlock keys together for around two to three seconds you can switch between silent mode and horn mode. Hooe that helps...

If you have your owner's manual, there is a section that will tell you the exact sequence to press to enable/disable the horn bonk. It has three settings, chirp, honk, and off. The chirp is a really quick chirp of the horn. Honk is a longer honk. Off seems to be what you've set.

I hope this helps.

You can remove the horn relay and use a Ohm meter and check the resistance between the horn relay connector terminal No. 86 (Black Wire) and ground. If the ohms are less then 5 ohms replace the horn relay. There are a lot more tests but as Polarcycle states you can do what he suggested other then I believe you have two horns in this vehicle.

You might can have the dealer program it not to honk, but its just the way the keyless entry works. I've owned 2 accords--an 06 and 08--and both of them honk the horn when the lock button is pressed twice. Pressing the button once will secure the car and arm the alarm. So once click is all you really need. And no your alarm is not malfunctioning.

Look in your manuel, there are steps to change the Key less remote setting to customize it the way you'ld like the car Key less system to work.
Good luck and hope this helps, if your still having problem. Just drive the Dodge dealer and ask the Service adviser to help you out, he or she would be more then happy to reprogram the key less system for you.