As the key blade won’t turn in either direction then the lock is seized.
Make sure the key blade goes fully into the key hole, if you aren’t sure; compare how far the key blade will go into the glove box key hole or the driver’s door key hole.
Open the trunk lid fully and squirt/flood with WD40 or Penetrating oil into the key hole through the Red aerosol straw, Pic 12 above, push the key in and out of the lock and turn it side to side as much as it will go. Keep trunk lid fully open for 20 minutes to let oil spread down throughout the lock, repeat above every couple of hours.
Don’t use force with pliers to turn the key blade, you can use finger force if the key is equipped with a key ring as illustrated in pictures above, you will get a better grip on the key if there is a ring on it.
The use of the emergency key blade to open the trunk is purely mechanical, there are no electronics involved, the vacuum pump, remote fob or switch inside car play no part in unlocking trunk with the key blade.
Dec, You hit the nail on the head. I undid the two bolts on the trunk lock and sprayed everything visible with WD40. I put lot of WD40 in the keyhole and around it while pushing the key slot in and out.Then I put the lock back and pushed lot of WD40 in the key hole and kept the trunk open as you said.
It did the trick! Now the metal blade key turns both ways and I can lock and unlock and open the trunk with the metal key.
So the mechanism was definitely frozen.
However, I am not sure if the following is normal.
1. When the car is centrally locked with the remote fob and if I use the metal key blade to unlock the trunk, all the doors also get unlocked and all the four windows roll down half way.
2. When the car is locked and I use the remote fob to to unlock the car, it still takes some time for the trunk to get unlocked before I can push the keyslot button to open it. Before it was never a problem.
3. If the car is locked, the trunk open button on the remote fob does not always work and when it works, it takes a long time to open the trunk
In any case, I want to thank you for solving a major problem. At least for now, my mechanical key is working again.
This forum is AWESOME!