It's always something...Can't get my trunk open!

[Human]

So I just got my '95 CS convertible back from the transmission shop this afternoon and a few minutes ago, I went out to get something from the trunk and found I couldn't open it, not with either key fob, not with either door/trunk key and not with the button in the glove box. I'd had it open earlier this afternoon to check if water had gotten into the trunk from yesterday's rains. The vinyl boot behind the rear seat was pretty full but amazingly, the trunk was dry. I opened it again after I'd vacuumed out the water to get a shop towel to wipe down the boot. Both times I opened it were with the key fob.

I went out a few minutes ago to get a transmission modulator I'd bought earlier in the summer and now do not need so I could return it to Amazon but as I said, neither key fob will open the trunk. All I hear is a faint click when I push the button, which is less than I get from the yellow button in the glove box. That one does exactly nothing. Both key fobs, however do unlock and lock the doors. The door/trunk keys do not unlock the trunk either, although they do fit and turn in the door locks. The door/trunk keys fit into the lock on the trunk but they won't turn. I can't believe that in two years of owning that car, I have never tried to unlock the trunk with the key, but that is apparently the case. This makes me think the trunk lid was replaced at some point and whoever did it didn't bother to swap the lock cylinders. but I don't recall the paint appearing disturbed on the bolts holding the lid onto the hinges, not that I ever specifically looked for that. There also aren't any signs of the trunk lid having been repainted.

So any ideas on how to get into the trunk non-destructively?

UPDATE: Okay, I got my trunk open. It took some forceful jiggling of the key but it relented and now it opens just fine with the key. It still won't open from the key fob, just the faint click, which leads me to think the actuator has gone south but that one's more in my wheelhouse than overhauling the transmission. Guess I'm gonna be making a trip to the junkyard soon. I'm assuming the actuator would be the same on a Regal, Gran Prix, Lumina or Monte Carlo from that era. I'll check the usual suspects online as well.

UPDATE TOO: to borrow a line from Lewis Carroll's Alice, this just gets 'curiouser and curiouser'. I just took a look at the trunk lid actuator and saw something I had never noticed before—a rather expertly installed bypass switch (see photo) to disable the actuator! It was done using OEM connectors to avoid any cutting any wires on the car, which is a touch I greatly appreciate—and the way I would have done it—especially since it allowed me to disconnect the switch and plug the wire from the car directly into the actuator. Unfortunately, neither bypassing the switch nor flipping it when it was connected would restore full key fob function. I heard the little click regardless of which way the switch was flipped. I also tested the switch with an ohm meter to make sure it functioned properly and it does. I also now know with certainty that when the switch is flipped toward the driver's side, it's in the 'on' position and flipped toward the passenger side is off.  I have left the switch bypassed for the moment but I will reconnect it when I replace the actuator.

Edited September 18, 2020 by Human
Add photo and more information.

[ron350]

 I think I would bee removing that key lock and find out what is going on inside that.

[ManicMechanic]

The switch is factory.

[Human]

1 hour ago, ManicMechanic said:

The switch is factory.

Interesting. I've never seen one like that before. Surprising they would use a generic, hardware store switch instead of something proprietary. I've had other cars that had a factory bypass switch in the glove box, usually right next to the trunk release button. This placement actually makes a whole lot more sense.

The key lock is working fine now. I opened the trunk with the key several times this evening and it's been working fine ever since I jiggled it loose. I'm not going to remove it until I get a new actuator installed and can open the trunk with the key fob as I don't have a 100 percent success rate reinstalling key locks.

Edited September 19, 2020 by Human

[ron350]

If the key I working now just give the lock a shot of WD-40 or your favorite spray lube that has one of those red extension’s.

 

Years ago my key got stuck in the trunk lock and I had to remove the lock assembly and repair it.

[Human]

So I went to the junkyard today and got an actuator off of a 1996 Buick Century--same part with a different electrical connector and no hole for the lockout switch. Before taking things apart on the convertible, I decided to do a little experiment with my voltmeter and connected the red lead to the wire that goes to the actuator and grounded the black lead to the body of the actuator. I pressed the trunk button on the remote, heard that same faint click but registered no voltage. It would seem the problem is further up the line.

[Human]

I love it when car problems heal themselves but I still wish I knew what caused it. Just for fun today, I tried the remote for the convertible and the trunk opened right up. Three more tries and it worked consistently. I reconnected the lockout switch, tried it twice more and no failures. I guess it's cured but I don't understand what went wrong.

[ron350]

A relay in the Remote Keyless Entry Module controls 12 volts to the trunk lid solenoid.

Sounds like there is a flaky solder joint in that module.