All of a sudden my entrance via key fob has altered. Instead of just flashing indicater lights when I press the key fob the horn sounds but still opens the door so it still works but annoying, any help would be appreciated.

 

sounds like your alarm system may not be arming because one of its sensors is open, so the truck is locking and notifying you that the alarm has an error. does the dashboard alarm indicator light do its usual flicker and blink?

 

Thanks for your reply Mollusc and after investigation I found that operating the 'lock and unlock all doors' with the button from within the truck it reset and cured the problem. Thanks again.