Liftgate/trunk no longer locks
 

With my 2001 Rx300, I noticed that when I hit the Lock button on my remote, all doors lock but the liftgate/trunk. Yes, the latch closes, I have checked by physically closing the liftgate and lifting it very hard (it stays put) as well as by sliding the latch up with a knife and trying to pull it out (it did not move until I popped the handle). But, when I try to use my remote to lock the car up, I can still pop the handle and open the trunk right away as if it never locked.

I realized when I experienced this tonight, that normally I would hear a loud "clunk" from the trunk door when I hit the Lock button and the trunk would be locked shut. This time, however, I hear only a faint, very soft "click" from within the door. I think what should be replaced is the trunk door lock actuator if I am understanding the problem correctly, since the latch can open and shut but won't lock electrically along with the locks on the doors. What is the part number for this actuator? I have tried searching for this on eBay but the results vary wildly for some reason. Any help is greatly appreciated.

If the hatch will lock/unlock manually but not with the key fob, it is the lock actuator.

But thinking more about it since I don't have my RX300 with me at the moment, that is assuming there is a manual lock button for the hatch, but I could be thinking of my van.

Lexmus is right. Confirm that the key can lock and unlock the hatch.

Once confirmed, you can pop out the lower portion of the covering from inside. Check the electrical connectors are firmly connected. The lock mechanism is connected by a rod from the actuator, confirm that the rod and links are ok. Then do the continuity check and replace the actuator if needed. 10mm nut driver is all you will need.

Salim

Thanks guys. No, surprisingly there isn't any manual switch for the lift gate lock as far as I can tell, unlike the cabin doors.
I attempted to set the lock this morning with my key, but for some reason the key does not rotate. There is a lot of resistance, compared to the lock cylinders of the doors. Since the same key works for the ignition, doors, and glove box with practically no force needed, I am inclined to think the lock cylinder for the hatch was replaced by a previous owner, but for unknown reasons it was not keyed alike to the other locks. (pity)

If the actuator has failed, I need to replace it asap. I live and work in Chicago and park on the street almost always out of direct line of sight, and I don't feel comfortable knowing that anyone can just walk up and break in by opening the lift gate... Of course there are already other precautions in place (dark window tint obscuring the view into the trunk, Viper security system equipped with a blinking blue LED on the windshield to show potential burglars that the vehicle is alarmed) so nothing has happened yet, but I only need this for my peace of mind. Can either of you confirm if this is what I need to order? I didn't get a chance to take a good look at the inside of the lift gate door yet. https://www.ebay.com/itm/99-03-Lexus...d/153095674275

That looks correct. The part looks identical to a part labeled with the correct part number.

https://ebay.com/itm/00-LEXUS-RX300-...0/371973600087

It is easy removing the inside cover of the liftgate, which I did to install a rear camera. So I doubt you will have much trouble replacing the actuator. Salim always recommends to leave off the cover after swapping a lock actuator to make sure everything is working properly, so you can easily fix a mistake if the door won't open due to some repair error.

Great. Order has been placed, should receive this by end of coming week. Hopefully this will work for me, but as the seller is generous enough to offer free shipping and returns within 30 days, I won't be out the $43.00 I paid in case it does not!
I will come back and update when I do the install..

If the key can not operate the lock
The key does not match the cylinder
Or
There is a mechanical binding .. rust etc. In this case the actuator will also not be able to lock/unlock.

Salim

Salim, I understood what you are saying, but the unfortunate truth is that I have tried, at various points in time over the last 4 years I've owned this vehicle, to use the key in the lift gate lock for whatever random reason, and each time the key did not turn at all. So I do not think the actuator failure had any influence at all on the key being unable to turn in the cylinder. Only I was able to ignore it until now; this event made for a rather nasty reminder of that fact for me :rolleyes:

Anyway: I actually took a minute to pop off both the soft and hard covers of the inside of the hatch door (below the rear windshield) before I left for work this morning, and I found out a useful fact! With the hatch closed, if you reach in to the door innards from the back seat and gently press *down* on the brass-colored rod coming down from where the key cylinder is, you can in fact move the actuator into lock cycle and lock the lift gate latch. Pulling *up* on this rod will reverse the actuator and operate the latch unlock. So now, once this rod has been pressed down, I cannot open the lift gate at all from outside just as if I pressed Lock on the door switch or my remote, until I go back and pull the rod back up toward the lock cylinder, which (thankfully!) temporarily solves my problem of keeping the car secure against thieves for the time being.

Since there isn't any friction or stiffness apparent in the cylinder action when manually actuating the lock, I think it is safe to conclude it is merely an actuator failure, which hopefully the replacement on the way will take care of.

When I bought my RX 300 the key at first wouldn't even fit in the rear hatch lock cylinder. At this point, I could have accepted that some previous owner had changed cylinder. However, since it's an old (and on some spots extremely rusted) car I figured it was probably the right cylinder but a matter of corrosion inside. So, I started spraying a mixture of penetrating spray, lock oil, and rust eater inside the key hole. The key would still not fit but I used patience and knocked it, gently of course. In five minutes of smooth knocking the key went in half an inch or something. I sprayed some more and waited, knocked some more, and soon the key went all the way in. It would take an hour or so of more spraying various **** in the hole before the key actually started to move. Anyways, in total, it was a victory and the cylinder is now working properly. This is also how I learnt that the RX 300 is equipped with some sort of alarm system. If the car is central locked and I go and try to unlock the rear trunk using the key the vehicle starts sounding and blinking until I press the unlock button on the key. Neat feature. Anyways, this story is a bit off-topic but I thought I'd mention it.

Also, the actual trunk handle was not working properly when we bought the car. In short, the "spring-back" was not doing it's work, so after pressing the handle I needed to use my fingers to let the handle return, when it's really supposed to do so on it's own. The handle has OEM # 69023-48010 and is not a fortune but still, money. I tore out the inside trim of the trunk and got the thing out. I feared that the spring had snapped because of rust. However, the spring was the most shining and clean part inside my handle, but everything else was a dirty mess. Big chips(!) of rost fell of when I scraped with a screwdriver. Big big chunks of rust. Most people had probably thought "***** this, I'm ordering a replacement!" but I stood in the bathroom with a wire brush, a scraper, and tons of lube. Finally I got the mechanism back on track. Feels so damn good, my wife was becoming really annoyed about the handle not returning correctly.

It always amazes me how much I am learning from reading the posts on this site.
Thank you, Gew, for inspiring me with your story. It turns out, I did not even need lubricant. All I did was just insert the key, and rock it left and right with increased force.
Within seconds, the cylinder was freed! Now, I am able to use my key to lock and unlock the trunk! (I did spray a little bit penetrating oil into the key hole just in case.)

Ok guys, a little update:
A few days ago, I got the chance to go to my local USPS to pick up the lock actuator, and it was only today I found time to attempt the replacement. However, till now I have spent more than 1/2 hour at this and haven't been able to determine how to take the lift gate door apart for this job. If anybody can provide some pointers, I would be very grateful. I already tried to search the forum, but I found no thread discussing this in detail. Thanks!

Going by memory ...

Bottom panel is simply snapped in. Pull it starting from one end and do not separate more than couple of inches till all shapes are removed.

The next section is also snapped in but you have to lift towards the glass to free it up ... check for screws but I dont think there are any.

All the mechanical stuff is in-between the sheet metal. 10mm wrench is all you need.

You can look up the diagrams by visiting on line parts .They show all snaps and nuts and bolts.

Salim

Sorry for delay in getting back to you, I unfortunately got a little busy and have not been able to tackle the problem since Thursday..
I will try again when I get some free time, hopefully Tuesday.
Thanks again!

Hey guys
Sorry for delay response, but just wanted to post a quick update.
For the past month, I tried many times to dismantle the trunk door. But, I never was able to figure out how to take it apart and replace the faulty actuator :(
I finally took the vehicle in to the shop this week and left it there with the replacement actuator. The next day, I was able to pick it up, and the trunk lock now works, lock and unlock with the main switch and key remote now working properly.
Thanks anyway for all your pointers.