Okay, 2015 Keyless RT fob...someone save me $300.00 or so by telling me how I get the darn cover off key housing (FOB) to replace battery, before I move on to the traditional hammer method. Book says push button to unfold key and simply remove battery cover, then replace battery. Well, I have tried to pop it off and push (slide) it off without luck. Does it need to be heated or iced down first (kinda just kidding). What is the "trick"? Thanks.