This has happend twice to me now since winter season has started. I have a 2006 S60 FWD 2.5T. I start the car in the morn to warm it up and open my trunk (Using the FOB key) to get something and it won't lock when i close it. The first time it locked once the temp went up, but this time it's a colder day (temp staying below zero) and it won't lock. The latch won't move even then i insert and turn the key in the trunk keyhole to move it.. The latch also pops back up on it's own when i use my fingers to pull it out to at least catch the latch when i push the trunk down. What gives? I only see the 'rear trunk open' alert on the dash.

 

very odd. just thinking aloud, I'd suspect there's some electrical contact that is opening up when the metal contracts due to the cold or possibly a ground point that changes its resistance. I'd start by inspecting / cleaning all wiring connector contacts, ground points and then see if the latch needs to be lubed.

 

****! I've called Volvo and made an appt for tomorrow morn... and it's snowing all night here.. I have to fix this asap. Also when i went to the car this morning the interior of the windshield was all iced up. (Not the exterior) Took me over 20 min to defrost it with the a/c on full and using a cloth. Weird. I guess the windshield is messed up somehow to do that. I bought a small heat fan to help me next time.

 

if the inside of the windshield is iced up, it means you have moisture in the cabin - has it been warm recently then turned cold? feel the carpets after a rain - do they feel wet (indicating you may have a clogged roof drain or maybe there's a leak around the air intake etc to allow water into the cabin )

 

Carpets are dry after it rains.. It has just got really cold where i am. The nights before were only about 5 c° warmer. Looking at some vids on YT about this shows me this is a job i can't do myself. Need a drill or welding tools.

 

job meaning fix the rear latch or address the interior frosting issue? Not sure what vids you were looking at - but my gut says to run away from any fix for either of those issues that require drilling or welding. for your latch, worse case is the component is binding and may need replacing (should be easy enough to find a used part - try Car-part.com to find a yard near you). Best case is you have an connectivity issue that needs to be cleaned up. As to the frost issue, you may need to remove some of the interior dash to look around for any signs of wetness, corrosion etc. Do you have a short commute where your car never really fully warms up? You may want to take a long drive with heater on warm to see if that can dry out the interior.

 

About the latch job, this is the vid i watched:

And i came across this thread as well:
https://www.matthewsvolvosite.com/fo...+latch+locking

I went to volvo and of course they recomended replacing it with a new one.