Back hatch on 2004 chevy trailblazer will not open...

Not sure about your car, but on my Chrysler mini van the same problem happened. The problem was not the motor but the body control module. The unit had 2 relays, but the BCM actualy controls the unit. To replace the BCM was $450. I bypassed the problem by installing an on/off switch inside the car and activated the motor by by passing the BCM at the relay. That was 3 years ago, still works great. Your BCM may be the problem. Check the schematics of the relays and try doing the same.

If you don't have the manuals, your local library has online access to most service manuals that you would have to pay for. Many time you can get access to them through their website if you have a library card. If not, go the library and get full free access to all the major car service manuals for free!

from inside to the panel door ,on the middle is a cup hole (remove it)and open, after that open the door and remove the screws to the interior panel .you will see where the lutch it is stock with tar isolation ..clean that up and replace that draft hole with duct tape ..put everything back the interior panel screws .job done

check the battery in the keychain. or replace. Make sure the keychain remote doesnt get wet!

you may find that the rod that goes to the latch and the handle has fallen off, causing the door not to open. what you can do is try take the door card off with rear hatch still closed, and try to re attach it

/the back hatch wont open without the remote. Is there another way to get it open? Most trucks have a handle or putton or something. Does this truck?

I have this same problem currently...did you find anything out about it?

door lock actuator solenoid ( inside of door) needs to be replaced

I am currently having the same problem with my 2004 Blazer, after a little research I am going to try replacing the engine compartment fuse *** suggested. I will let you know if tis works.

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. 

your gas struts are bad. there's a recall for this from Toyota. Go to your dealer and ask for it to be fixed, even if you are out of warranty for free.