Land Rover Repair: Doors wont opn, electrical problem, hinges

Question
Hi, I have LR Disco 97 & first my back door on the driver's side would not open unless I held up the lock & opened the door & now the trunk is doing the same thing. I called LR repair shop (2nd best to dealer) & they told me they see it all the time and that it is most likely an electrical problem & if so it will cost more than $1000. I read some responses that said I just have to lube the locks--if that is so--why would they all be failing? is it electrical? & you said to replace the hinges--where do you get hinges & how do you replace them? could I do it myself??  

Answer
First, I never suggested replacement of hinges for the problem you are describing.  I do think you may have one or more bad lock actuators.  Those parts - $2-300 items - are in the affected doors.

Lubing the mechanism may work.  If it does not, you'll need latches and actuators.  And if that happens, repairs can be costly, as you were told.