i dont know if this is a problem with the bonneville in general, or not, both of my bonnies have back door issues, they wont open at all from inside and out, what can i do to get these doors to work again.

Could be seized locks and or latches. How cold is it in NB lately? Frozen? Is the handle button going all the way in? (ie sim. to locked condition) or is the button stuck? I'd think its the latch inside the door. Hard to get to when the door won't open eh?

Had the same problem with both my Bonnevilles when they sat for any extended periods of time. Had to pop the rear seat out and then take off the door panels. Then you can pop the latches from the inside and open the doors. Once the doors were open I took the latches out and cleaned them good with penetrating oil and then lubed them with chain oil used for motorcycles. This oil clings well and still gets to the pivot points on the latched. I ussally relube the latches every 6 months. To date the cars can sit 3 to 4 months at a stretch with no problems as of yet.

Had the same problem with both my Bonnevilles when they sat for any extended periods of time. Had to pop the rear seat out and then take off the door panels. Then you can pop the latches from the inside and open the doors. Once the doors were open I took the latches out and cleaned them good with penetrating oil and then lubed them with chain oil used for motorcycles. This oil clings well and still gets to the pivot points on the latched. I ussally relube the latches every 6 months. To date the cars can sit 3 to 4 months at a stretch with no problems as of yet.

how do i get the latch out from the inside of the door?

I had to pull the track and molding for the small rear window in the door to get at the latches. It was a pain but not having the rear doors open is a worse. Maybe you would want to try lubing the latches first and see if that works. I know that when I tried it on mine the fix was short lived.

i solved this very problem just the other day. i took the door panel off form the inside (since i couldnt open the door). it wasnt all that easy but i dod it anyway.

i found that the problem was with the outside latch so i oiled it severely from the inside. the thumb button was pushing in but it wasnt spring back which wouldnt let the door open.

i noticed my other back door was starting to do the same thing (too much dust and dirt around here i guess) so i fixed that one as well.

i might add that this isnt the first time the back door was stuck. last time the rod going from the inside handle to the outside thub latch had popped loose at the thumb latch end. a fairly simple snap of plastic clip, which was still there, and everything was working again.

good luck