trunk lock won't turn w/ key - 2010 Yaris Sedan

[06YarisRS]

Originally Posted by TYaris2010

used 2010 Yaris, 50k miles, car is relatively new to me.

Putting key into trunk lock, it will not turn (OEM key). As I haven't used the trunk, it must've been this way when I bought it but I didn't check when buying.

Sprayed Some PB Penetrant (similar to WD 40) to clean out gunk or whatnot, still no luck. Did this a few times.

Anyone else have this issue? how did you solve it?

Car is not old so I cannot believe that the cylinder is worn out. I am guessing the prior owner used the trunk release in the car versus the key on the trunk? so it got dirty over time & seized? or?

Any tips appreciated. Do not want to pull and install a new cylinder unless I have to.

Door locks work fine.

Have considered trying graphite in the lock but as of yet have not.

My '06 and '08 (both older when purchased) had lock cylinders that would not turn due to contamination. It is not so big a job to take the lock mechanism out and clean it. There is a snap ring that is removed and the guts of the cyinder slides out. The one on my '08 was seized so well that I had to put the body of the cylinder in a vice and wiggle the shaft back and forth little by little until it was freed. I then took the guts out, flushed it a number of times with contact cleaner, until it ran clear. Then I lubricated it well, reassembled it and it's worked fine since. Every once in a while, I spray a bit of electronics cleaner in followed by a lubricant.

Another member posted step-by-step instructions with pics here on the site.