No power on chevy trailblazer, door will not unlock with key as if there is nothing inside where key opens door, just back and forth,trien unlcking from outside thru window but no power so wouldnt unlock what can I do??tryind to open hood from outside to dissconnect battery but no luck..what can I do??

SOURCE: door in back cant open from outside and inside

I'm sure VW had a recall to replace door lock mechanisms around that age, check with your dealer. If the door and window on the same door are not working it could be lack of power to that door, check the wiring harness connection is still plugged in and ok on the b pillar (b pillar is the vertical panel between front and rear door), remove rubber gaitor bellows and check connections.

SOURCE: hatch-back door will not open

I can say I have had the same problem, only the back doors and the rear hatch/glass won't open using keyless remote from them freezing this Winter.  The front two driver/passenger doors will unlock with keyless remote but none of the rear doors, hatch or glass.  Since I had to replace the stoplight bulbs in the rear with one not working and I don't need a ticket on Memorial Day weekend (need to replace 2 at the same time is wise according to any good mechanic), I had to get the rear hatch open to get to the lamp assembly and replace the bulbs.  My thinking was that since my two front locks were opening but no others and my keyless remotes are working, it has to be a fuse or relay that is not working!  So, I talked with a NAPA rep and he said the "Day running lights" relay can be a temporary fix to get the rear locks open to replace the bulbs.  I looked up in the owners manual where both relay's are located and removed the "Locked" relay and "Day running lights" relay and put the "Day running lights" into the same slot where the "Locked" relay was not operating and it worked!  I got the doors unlocked and replaced my stoplight bubs replaced.  Now, I have a new problem, my Tahoe won't start!!  I'm assuming the relay wasn't supposed to stay in the wrong slot when operating the vehicle because I started the truck, and it started and died-started and died-same and again.  I think the wrong fuse can be used to fix another problem like a fuse.  But, a fuse you can leave in and deal with one operation in the vehicle not working until you can replace the fuse later when you purchase it.  But, not a relay!  Now, I think the confused electronics cause another component (possibly the fuel pump relay) to burn out with the wrong relay in place of another when the vehicle operates.  I should have known but I was so glad to get the doors open after two months and it being Memorial Day weekend.  Now I have to find out what else is wrong so don't make that mistake to avoid the same predicament.  Better to get the relay ordered and replaced than to have this happen to you. 

SOURCE: 2003 Trailblazer LTZ Tailgate and back window won't unlatch

I am not sure how to manually release the latch....

however,

if it is electronic, i would check the fuse for it.....normally though on the inside there is a little access to things like that, so you can manually open it...would be like a small lever.

SOURCE: Back hatch will not unlock/open

you could use some lithium grease and spray it in the general area of the latch and hope it lubes the latch enough to loosen it to open. but it will cause a mess spraying it

SOURCE: 2007 chevy tahoe driver side door handle will not open door

the linkage behind the handle either the retaining clip broke or popped off need to remove the door panel to check and fix

Testimonial: "Thanks I thought it might be a cable or linkage. Much thanks"