The rear hatch of my 2005 Chevrolet Equinox will not unlock.

Yes, you should be able to use the key to unlock the rear hatch of your 2009 Equinox even if the car battery is dead. The lock cylinder for the rear hatch is likely located on the outside of the hatch itself, or it may be located on the door handle. To unlock the hatch with the key, insert the key into the lock cylinder and turn it clockwise. If the key won't turn or the hatch won't open, you may need to wiggle the key or apply more pressure to unlock the hatch. If the key won't go into the lock cylinder at all, it is possible that the lock is frozen or damaged and will need to be repaired or replaced. You may also be able to use the manual release for the rear hatch, which is usually located inside the vehicle, near the driver's side door or on the underside of the dashboard.

First off, the sound you mention may be the "ka-tunk, ka-tunk, ka-tunk" sound related to the vehicle vapor recovery valve under and in the back of the car related to vehicle fuel tank vapor recovery. This electro - mechanical valve operates while the car is on or off.

During time when you can fully open the hatch, Start by cleaning the rubber seals all around the hatch with a silicone treatment to prevent sticking.

Spray a lubricant that will not harm paint into the 2 hinges inboard of the upper struts. Spray some lubricant onto a paper towel and rub down the shafts of the struts as well to remove any glazing that may have built up.

Inspect the exposed paint areas of the hatchway and the hatch itself for signs of scuffing which may validate intermittent heat swelling of a tight space requiring panel realignment.

The following can be dangerous so have a qualified mechanic;
Inspect the installation of, remove and test the function of the struts to eliminate a source of binding. The end of the strut with the rounded cap attaches to the car body.

Have a body person inspect the installation of the outer rain seal at the closed top of the hatch. I had a shop owner ask to inspect mine years ago as they couldn't see how it installed on a car they were repairing. Could be a source of hang up.

Hopefully, this helps.

This is a rotating latch assembly.
Assuming there is no physical door damage that keeps this latch from rotating freely;

• Ensure that little fingers haven't pre-rotated the mechanism so that it presents the wrong surface when the door is closed. Operating the electric door unlock feature should return the latch to the correct open position
• -It may be corroded. spray some WD-40 into the mechanism in the door and rotate it, release it with the electric release switch before trying to work it back open if necessary. If this is the issue, finish with some graphite lubricant spray once it is free again
• if the latch does not electrically lock, the choices for your mechanic are, the fuse, the wiring, the body and component connectors including one above the rear end differential which, is exposed to some nasty wet and muddy environments and the actual lock / unlock solenoid at the door latch.

Sorry for the varied answers but the question was a little broad. Good luck.

If there is no exterior handle to open the hatch you are in a pickle. The rear hatch interior moulding assembly will have to be removed from inside the vehicle to access the lock assembly. This may crack/damage the moulding assembly as it is not designed to be removed this way. Once removed the door can usually be opened manually and then diagnosed for the problem. It may be a defective lock solenoid or latch assembly. I would have a pro look at it as they know how to disassemble these things with minamal to no damage.

the rear hatch has a door lock actuator it sounds like its bad

Most likly is the rear hatch latch it self. should be to much money to do youself youll have to remove any int panles on lift gate unplug latch there maybe a rod or two connected to latch couple bolts and pull it out

I've had the exact opposite issue with my 2005 Equinox.
My rear door is locked and will not unlock.

We have to climb into the back and gently work the panel loose enough to go in with a long screwdriver and push on the lever on the lock mechanism. If you have a flashlight and some patience, you will eventually pop it open. Good Luck

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

ive got a 07 equinox and the rear hatch wont open as of yesterday. on the inside of the hatch there is an access plug you can pop off and inside you'll see a metal switch with a hole in it. if you push it away from yourself, it will unlatch it. i dont know why the hatch wont open as ive checked the fuse and its ok.