My horn sis not working. There was trouble with my car alarm months ago and the repairman removed the after market alarm. However, my car failed inspection today because the horn will click but does not beep. Can you tell me if I just need to plug something back in?

MK49 jeep 2010. usa answers me...
well buy the service manual or rent it

https://eautorepair.net/Marketing/Default.asp

there is no secrets here on this topic at all
just the lack of no book in hands or PDF
is this car USA spec car? not told country of VIN
so all I can do is tell you how OURS works,
for sure this simple thing (well is not simple like in 1990 and before) (alarms added and more)

not scanning the PCM first is failure #1
the MK49
the TIPM Tipm the SM shows a relay deep inside TIPM for horn ,but is vague o n location.
under hood, totally integrated power module.
has 3 honk paths or more.

here is the path horn fully.(path1 horn button)

horn button pressed or switch here bad.
goes to clock spring (not bad)
then to cluster brain,(honk commands)
to TIPM brain, via fuse F28 there.
and TIPM DRIVES THE HORN directly.

or an alarm trips the horn. visa CAN_bus network commands, and again not scanning , the obd2 port you will never learn why it fails.
chirp mode (keyfob decoder), alarm or the horn button fails. 1,2,3,
3 ways to fail, and more.

not scanning the OBD2 PCM port is why you do not
now what is wrong.
B2336???? 2339 horn switch stuck DTC> amazing no?
com fails if any kind (DTC)
the horn also has chirp logic (disable it is wise)

"Using a transmitter programmed to the Sentry Key Remote Entry Module, the status of the horn chirp may be toggled by the customer."


or the alarms on the car is failing and sending horn honk commands via Can-bus network; Unnnn codes?
CAN_BUS B and C must be error free (or LIN bus)

no alarms , no chirp mode junk enabled.
here is no internal schematics of the TIPM at all
so how it directly drives the horn is not shown.

scan it first. not last. or go broke fast. guessing wrong.

hi michelle
is the alarm system after market or did it come as a factory unit
you will need maker of unit to disconnect the horn from alarm system and still have it work on the steering wheel horn button

I would check every single fuse in the car. Blown fuses can cause weird issues like this. While the initial issue with the mechanic does sound like an alarm problem....the rest does not unless the shop that installed it really butchered the job.

Change the battery in the key and use the key to turn off alarm.

If you need further help, reach me via phone at https://www.6ya.com/expert/frankie_091f536560a54e12

does the horn work from its button? if does then has a connection fault,or the alarm has a seperate audible component that has failed , is it a lexus factory alarm or fitted after market ?

Hi, I am not sure where the switch is but 3 months ago the following was posted by:-


liverhuyen2003 answered 3 months ago
Make sure the drivers front(left front) door is closed and you have your car keys. Insert your door key into the drivers door and turn it to the locked position two times. Then turn the key to the unlock position twice. The alarm should be disarmed, now.

SECOND TECHNIQUE: If not then take the ignition key and turn the ignition switch all the way ON then OFF then ON a second time and OFF again. These are the procedures for nearly all factory alarm systems. If neither of these works you probably have an after market(add-on) alarm system.

Warnings This technique is only for use on your own car that you own and have keys for. If you don't have the keys- disconnect the negative battery cable to stop the horn until you get your keys. Then reconnect the negative terminal and proceed to step one.

Hope this helps!

To Larry Crowley,
Did you ever correct the problem to your 2000 Jeep Grand Cherokee and did you in fact determine that the problem was in fact the Body Control Module (BCM)?
I too have a 2000 Jeep Grand Cherokee Ltd with 162,000 miles. Up until just a few months ago, I never had any major problems with the car however in early December one evening the car was turned off and parked in my garage and the horn just went off out of nowhere, a solid horn...it was deafening! We unplugged the battery for the night so it wouldn't drain the battery. The next day I took the car to the mechanic who replaced the horn switch and relay. We thought that had fixed the problem. An hour after I left the mechanic with the car both the BRAKE and ABS lights on my dash went on and my speedometer stopped working (very scary to drive that way). When I stopped the car and went to lock it with my keyfob, the solid horn went off again so obviously the problem was not the horn switch and relay!?!? Over the past few months I have had my car to three different mechanics as well as the Jeep dealer and they have all concluded that the problem must be the BCM but they said that the only was they can properly diagnose the car is if it is acting up with the above mentioned symptoms while in the shop. Unfortunately it only acts up intermitently, not all the time. I am at such a loss. Currently we have removed the fuse for the horn so I am driving with no horn which is extremely unsafe! I look forward to any advice you have in this regard. Thank you!

If you have an after market alarm installed remove the in line power fuse from the alarm and see if that resolves the issue. I would look at the horn buttons on the steering wheel for the fault first as this is the most common area of a problem. If that checks out then you will need to check the horn itself. After that the only place left is the ECM or a short in a wire.

There is a hood open switch on many after market alarms that can cause the condition you speak of.

Also there is a chance that the engine starter solenoid internal contact has failed for the start circuit. You can check this with a healthy screwdriver by shorting from the positive lead to the terminal. (YES It SPARKS!) If the starter engages then the solenoid is fine. If it does not then the the solenoid has failed.

Another thing that can cause what you speak of is the alarm motion sensor.

If you really want it fixed... like NOW go to any auto alarm installation shop, grab an install tech and take him to your driveway.... (with a borrowed car if need be) My bet is he will have you going in less than 15 mins and for a reasonable charge.

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.