2000 Other Mitsubishi Models Horn goes off in cold weather w

Hello, my wifes mitsubishi's horn goes off in the morning when its cold, it usually stops when you bang the steering wheel, but sometimes it does not until the temp. rises. I am assuming that some how its binding or freezing up inside the steering wheel, but what confuses me is that you need to depress the horn to activate is, how can it activate in the morning just by inserting the key and turning on the vehicle. I am not sure how to pull the cover off the steering wheel, it is tight, don't want to break anything, it does have 2 torx screws behind the wheel, is that to loosen the cover to access that mechanisim? Any guidance would be appreciated.