Why on cold nights ,would the horn start blowing and the interior light come on? on 1995 Chevrolet 1500 Pickup

Only when temps are below 25.

Asked by for the 1995 Chevrolet 1500 Pickup
ANY aftermarket/dealer add-ons , such as keyless entry or aftermarket radio , security system? Had any kind of collision/body work done?
1 more answer
have shop check