I need a new driver door latch for my Jeep Cherokee

Search amazon.com for "Chilton jeep grand Cherokee" and you will see results for both Chilton and Haynes repair manuals. You might also be able to find the same book(s) at your local AutoZone or NAPA store. Amazon com chilton jeep grand cherokee

Probably the spring broke which returns the latching mechanism to its "open" position. Pull the door handle and hold it. Take a screwdriver and flip the latch (catch) in the door to the open position. Now, you should be able to close the door 1 time, and it should latch. You need to replace the latch mechanism as soon as possible. You can get a used one from a junk yard. Some on-line parts stores also have free on-line repair manuals which show how to disassemble the door and replace the latch. It is not a difficult job. Anyone with some basic tools should be able to handle it.

11 is no reference signal from cam position sensor (distributor) 12 means you cleared the codes before that test, 25 deals with the idle air control motor...possible wiring or open circuit.
Make sure you check all fuses before going further. A blown fuse can give all kinds of strange codes. Then go back to testing components.
http://www.scribd.com/doc/18999822/Jeep-Wiring-2. Diagram is for a 93 but is pretty close to what you have. Test procedures are contained in chilton and haynes manuals...I prefer chilton as their wiring diagrams are more accurate.

Yes, it would involve removing the door panel, disconnecting the actuator rods connected to the latch and unbolting the latch from the door.

pull the inside door handle out like you are opening the door, and use a screw driver to move the latch.

Latch assembly is removable. Likely has "star" bolts holding it to the door. Inner panel needs to be removed to get it out after it's unbolted. Most inexpensive manuals like chilton or haynes have decent instructions for procedure. (not difficult but too long to re-write here.)

Most larger parts stores carry either chilton or haynes manuals. They are far from perfect and their wiring diagrams are pretty much junk, but overall the do have enough info for most basic and some not so basic repairs. Chilton also offers a download for pay which is better but unless you are doing major complex repair work, likely you won't need it.

known problem replace the door latch/acuator.

Give latch mechanism a good spray with white lithium grease or similar also, in case latch is sticking slightly.

You will need to replace the latching mechanism. There is a small access door near bottom of the panel that you can manually actuate the mechanism, but if it was like my experience, the mechanism was frozen and you will have to slide a coat hanger down into the panel from the top and pull the cables