Why don't front door locks work, either in response to fob or buttons?

SOURCE: Remote door locks won't work

There is a flash for the body control module for this problem. You need to go to the dealership to get it performed though.

SOURCE: 2002 Dodge Grand Caravan Driver Door Lock/Unlock Switch

sorry not sure the 12v prob will help this swtich works on 5v off 3v unlock 1v lock single wire lock/unlock logic signals
I found wiring diagrams at
http://www.dodge.com/bodybuilder/2004/docs/wd/rswd/tc.pdf
it is 2004 but use the wiring diagrams to test the wires
(most likely to fail where they flex)
because it is using logic gates disconnect the plug at each end of the wire you are testing or the damn thing will find a few diffrent ways to trick you.

SOURCE: Remote key fob does not

check the fuse dude it is by driver door side under driver seat.

SOURCE: 2006 Dodge Caravan - ONE power door lock stopped working

i have replaced many sliding door lock actuators on these vehicles..dealer part..mostly on passenger side sliding door..also possible you have a broken wire in door track harness..follow wiring from door into what looks like a plastic chain in door track at door opening

SOURCE: 2005 Grand Caravan power door lock quit working.

The lock actuator is probably broken in that door. We got one of the internet for 80$ and replaced it outselves and it solved this problem. IOD fuse is very temporary fix as system is sensing problem and flipping to protect itself like the breaker switches in the house.