Next time it starts blowing, open the fuse panel door and pull out the HORN RELAY, it should stop! Something is telling the Horn Relay to activate, could be the horn switch going bad, a faulty relay, or water got into relay?
From the FSM:
HORN SOUNDS CONTINUOUSLY
1. Faulty horn relay. 1. Refer to horn relay for the proper diagnosis and testing procedure. Replace the horn relay or repair the shorted horn relay control circuit, if required.
2. Faulty horn switch. 2. Refer to horn switch for the proper diagnosis and testing procedure. Replace the horn switch or repair the shorted horn switch circuit, if required.
Check windshield for leaking water down onto fuse and relay panel!

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Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited 
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