Locked out!!!
 

How does one get into a 126 with the keys locked in it? I have been trying two different slim jims for about 2 hours!

Dealer
 

I believe with the VIN# and proof of ownership, the dealer will (for a fee) make you a new key.

http://www.peachparts.com/shopforum/diesel-discussion/248652-these-old-cars-easy-break-what.html?highlight=break+into

Check this thread out, I'm not sure exactly how to do it but I remember reading that it was fairly simple

Yes, this will work. Be prepared to spend some time. Not expensive, cost me $14 a key and they'll have it for you the next day.
I don't understand how you can lock the keys in the passenger compartment, I can't close the door with it locked, a safety measure.
On my 126, I can't push the button down when the door is open.

The door locks on my 126 are possessed they lock by themselves 15 seconds after unlocking the doors unless the car is running. which i have noticed sometimes that all but the driver door will lock with the car running. I have checked everything. nothing seems to be wrong. and you are right the driver door lock will not lock with the door open. but with closed they lock all by their lonesome.

Ah, you have a poltergeist. I have a key ring that allows me to remove one half, I keep the valet key in the ignition and the master key on the other end. You may need to keep another key in your pocket so you can unlock.
Not sure how to trouble shoot that, as the lock system is independent from the engine.

It seems as though this is the design of the beast. i have done so much trouble shooting and had everything apart and it all seems to be functioning properly ... i beleive it is just a "feature" to lock automatically.

You do not happen to have an after market security alarm installed in the car, do you? It is hard to imagine it will lock everytime after 15 seconds. Plus the fact that it will NOT lock if the car is running. This implies the 'security device' knows the key is in position 2.

no after market and everything is stock ... i have checked for leaks ... i have checked for wiring shorts ... vacuum system is flawless switches are functioning

I posted pics on your other thread, the FSM test procedure.
Good luck.

EDIT: Mine does not act as yours.

Have you had the driver's door inside panel off yet?

I had the exact same problem with a then new-to-me 1991 300TE. It even locked itself once at the dealer after they pulled the car around after some service. It was caused by an aftermarket alarm system that I didn't even know the car had. After I disconnected the aftermarket alarm, the problem never reoccurred.

I have had the entire interior out of this car i am 99 percent sure that there is no aftermarket alarm or any aftermarket parts at all (except the radio which i installed). i have had all of the door panels off and have tested the entire vacuum system.

One thing to mention though i fixed the trunk latch and during the testing the stock alarm system started making the marker lights flash but no horn? i put the key in the driver door and turned it to unlock and the lights stopped flashing

Its not a feature of the stock setup, but perhaps a feature of an aftermarket system? If its after 15 seconds every single time I'd look into various places and try to find a aftermarket security device.