My driver's side rear door is also frozen closed ('99 Ram 1500 purchased new). The passenger side was acting up and the lower latch was rusted, but I lubed it up good before it seized. The rear door handle cover (and handle) comes off with two torx screws, and there is no cable used, but two rods, one connecting to the top latch and one to the bottom latch. I'm going to try sliding a slim jim in at the bottom of the door to try and move the frozen latch. I've sprayed all kinds of penetrating oil down there, with no results so far.

 

The handle in the door jam facing the front door is indeed a rod going up and one going down. The inside handle uses a cable, which is prone to breaking at the plastic retaining end of outer jacket.

Panel will come off with door closed, but it is not easy. The metal clips at the rear edge by the window will come off the panel. Remove panel, and reach inside at the front conrner of the door and spray some penetrant all over the latch mechanism at the bottom. Using the outer handle, keep working it and it should eventually break loose. Do not use the inside handle as it is likely to break while latch is stuck.

 

have friend on out side of door pulling latch you on inside and kick the stubborn bastard open. i have to do mine just liked not having to move sub from behind me, its like a massage while driving. that should do the job to get door open.