I have been having problems with my dealer installed car alarm. I have very little faith that car alarms actually help with vehicle theft, but the dealer installs alarms on every car that they sell.
To date, I have been back to the deal 3 times with problems with the alarm. Yesterday, they suggested that I pull the horn fuse to stop the horn from blowing when the alarm is acting up. In looking at the fuse box and at the manual, there is no horn fuse listed. Today I had the alarm fixed one more time and the dealer was not able to tell me where the fuse was! It took them 2 hours to get back to me with the answer.
The answer is, there is no horn fuse on Dodge diesel trucks!. The ECU will de-activate the horn if it is honking too much. So if the horn is honking, the only way to disable it is to pull negative battery leads on both batteries, pull the horn connector, or pray that the ECU will disable the horn before the neighbors come out and shoot holes in your truck!
I was also told that if I did the mod to make the remote keyless entry open all 4 doors that the alarm will go into panic mode!