Key is locked in the trunk. The release button inside the car will not release the trunk. Any thoughts. The alarm is going off but we are not able to get the trunk open.

If there's no other way, have the dealer make a key for your car. They just need your VIN number.

TRY OTHER DEALERS, There must be a dealer that will make you a key. Tow your car to the dealer and tell them to fix your trunk lock, so you can get your keys.
Better than using a can opener.

Ford sold a Ford branded alarm through the parts department. These sometimes were a dealer installed option on new cars. Mine would randomly stop responding to the remote and I would have the same symptoms as you describe. I had it removed and the original equipment factory system still worked. Be warned, if you have the Ford "accessory" alarm, your key fobs (remotes) are different and the method to program them is different from what you will read online. You can tell if you have the system by looking at your key fob. The standard Mustang key fob is a 4 button (lock, unlock, panic, and trunk). The accessory alarm uses a 3 button remote and clicking unlock twice would pop the trunk. I really wish I had a picture of the remote because there are 3 button Ford key fobs for cars without a trunk release although I don't think you should have one on a Mustang. Long story short, if you have the accessory alarm, you can solve your problem by having it removed but you will need new 4 button key fobs to remotely lock/unlock your doors

Unlock door with valet key to shut alarm off and remove the trunk release switch. Jump the trunk switch wires together for a second and it will open

What is wrong with using the key.

I suggest getting a helper. While you sit in the vehicle and press the button inside the passenger glove box, ask your friend to lift the trunk. If your friend can open the trunk easily, your torsion bar needs to be replaced. This acts a bit like a spring to push the trunk open when the lock releases it. Another issue could be the lock release has gummed up with dust in the lock grease. You vehicle is 21 years old and grease thickens up with dust and such over the years.






Good luck.
Semper Fi,
Z

Checked all the fuses? I assume your trunk has no key cylinder.
Can you fold down your rear seats? Many times there is a manual release inside the trunk, just incase you lock yourself in the trunk!
If there is no manual release lever or cable with handle to pull the latch itself may have a slot on it that when a flat screwdriver is inserted and twisted it will rotate the release.

Sometimes you will find a button inside the Glovebox. This is an Electric trunklid release. Some of the models had controls on the lower drivers door along with the Gasflap release. It depends on the Series that you have. The S, and GS, had less features than the LS model.

You can go to a Locksmith and they have a box of keys and will try them until one opens your trunk. Then you can have a key made to match your lock.

I don't believe the inside releases were made standard in 1992.

1.doors will lock when you start engine,(autolock)
2.are you using service key in trunk lock? it wont go in all the way,(try another key)
3.have you tried turning key fully to the left then button release/turn key fully to right then button release,(valet lock)
Still have a problem?please feel free.....
car supplied with 3x keys and 2x remotes when new...

try hitting the button again to release the latch or put the key in the trunk cylinder and turn it to open as if you would when trunk is closed

cable knocked loose and key wouldn't work if it did previously. last option, obtain acess from back passenger seat and pull aux cable or force lock open, as far as the key issue, call a locksmith