XC90 Rear lock failure child lock closed

[precopster]

About 5 weeks into getting our XC90 on the road and my wife reports the rear hatch won't open any more. Activating the remote operates all the door locks without a problem except for the rear hatch lock.

So I crawled through today and opened the hatch from the kids seat area via the escape handle. Sure enough after closing it again it still wouldn't open by the remote again. I then managed to open it by the escape handle. Once I did that I flicked across the rear tailgate manual child lock button which then disappeared into the cavity. I was unable to coax it back to the "child lock off" position.

That was a bad move because after closing the tailgate it no longer opens by means of the escape handle. It seems ludicrous that you can even lock children inside a car in the 7th row with no rearward means of egress. Not a very safety conscious design.

So now I can't access the rear lock screws or trim panel edges so I may have to drill holes in the rear trim to place the electronic lock into the open position or recapture the child lock button.

I'm hoping I can avoid this if somebody can help with a less destructive suggestion. Any ideas at all would be greatly appreciated. Cheers Mike

[SuperHerman]

Precopster: Unfortunately my XC90 doesn't have this set up as it didn't come with third row seating. I had similar problems with my outside handle not working as the cable stretches and fails to work as desired. You either have a failed solenoid or stretched cable.

As to your specific problem working from the inside - I suggest you check Ebay for some reference pictures.

http://www.ebay.com/itm/2003-2014-Volvo ... AB&vxp=mtr

I noted one listing, linked above, that has a good view of the red button which I believe you are having issues. It has an "ear" formed into the button (not sure if it is at 12 or 6 o'clock) - which I what I think you need to mimic to get the inside handle to operate. Maybe you can fashion a piece of stiff plastic or metal with a bend that may allow you to manipulate the mechanism to unlock.

Other than that the only other nondestructive option is to see if you can peel the upper part of the panel from the lower part of the window back a sufficient amount to gain access to one of the release cables. Next would be trying to cut a clean square which could be glued back on with minimal showing. I am not sure if strategic hole drilling will get the panel off.

[precopster]

The child lock being on prevents operation of the internal handle. This is inherent in the design.. After searching here on MVS a couple of other posters here on MVS experienced the same thing after their rear lock failed. After they flicked the child lock on they lost access to the hatch handle which is what the child lock is meant to do.

However removal of the rear panel is not as bad as I thought. There is a torx 20 just inside where the handle is located and also another one just inside the light enclosure on the other side. Then the panel just pulls off. Now to find a new lock : never a used one when they fail at 11 yrs.

Thanks for the photos as they may help to gain access to the panel.

[scot850]

Expensive though a new one is, chances are any used ones (unless same part used up to 2014) will be as likely to fail again. On a safety critical item it may not be worth using a used part. In fairness, I have used used catches on 850's and V/S70's that are still working well at 20 years of age after cleaning and a bit of lube.

Neil.

[precopster]

I pulled off the rear panel. The tailgate is actually made of fibreglass just like the hood of my old 960 wagon I used to own.

Once the panel is removed I'll need to mangle the rear lock assembly with a large drill. No amount of cable pulling or coaxing will make it open. I really wish I had left that child lock in the unlocked position so I can simply open the hatch via the escape handle.

Will post photos once I get another lock in my hand.

[precopster]

I received a used lock from a dismantled XC90 for $85. Also by receiving the used lock I discovered a position on the used lock where I can access the child lock mechanism. I took a photo to show this below. The blade of the knife shows where to pull anticlockwise to open the child lock with a small flat screwdriver. This hole in the lock can be accessed from inside the car when the rear tailgate trim is removed.

[precopster]

Replaced the lock yesterday. Same result. Handle won't open the latch. I opened up the old lock and noticed that the slide mechanism powered by the motor is sitting in the locked position. When I slide the mechanism over to it's unlocked position the release handle works fine. The cable actuation for both handles is pushing not pulling so a stretched cable isn't possible. Hats off to Volvo for a great design here.

So the issue is with the signal arriving from the rear body module or REM. I removed the motor mechanism and tested it on the bench and it works fine.

I'll need to put a dummy load (such as 5W globe) on the connector going to the lock and operate the remote to see if there's a voltage. The only other variable may be that both locks have faulty microswitches.

[precopster]

Tested the REM in Activations today in Vida and the Unlock relay on the REM cannot be heard at all. The lock relay is audible. There are no separate fuses for the rear lock.

Looks like a replacement REM is the next step.