Hi Guys, I have a 2005 jeep grand cherokee, the horn goes constantly when the key is first turned on and runs for about 30 seconds and switches off.

I couldn't enter the vehicle Vin number into the details as when i choose the engine there is no option for a diesel engine. sorry

I connected my snap on ultra to this vehicle and once again the correct info cannot be given as the scanner has no option for the engine. I have just selected the 5.7l v8 petrol. My issue is with a body function so i hope this wont be trowing my results off.

Anyway like i said the horn goes off when the key is turned on and goes constantly for 30 seconds. codes in the SCM says the the horn switch is stuck. i have disconnected the airbag side of the clock spring with the horn switch wiring, and i still get in my data that there horn switch is set, i have tested the horn switch and that is fine.

the horn relay is controlled via the FCM and both SCM and FCM communicate via CAN, This is how my diagram is from Alldata (again doesn't have my exact car)

My question is has anyone seen this before? Before i condemn the SCM is their any other things i should check

Also will a New SCM need coding/programming to the vehicle?

Blair Rosson
Technician/Owner
Blairs Auto Electrical
Paraparaumu, Wellington, New Zealand