93 300E doors locked when connecting battery

Recommend that you unlock car and leave door open next time. This time, simply break a window and crawl in, being carefull to avoid any cuts on the broken glass. Or you could simply break the glass in a door window and then reach in and open the door. Or simply use a crow bar to open the trunk and then unscrew the back of the back seat once you have accessed it through the covering panels in the trunk. As an alternative, you could simply tow it to a street in a big city slum area. Leave it there. Watch from a block away and eventualy someone will come along and open it to hotwire it. At that point, take out your gun and shoot the thief and their buddies, get in the car, and drive off. But I would advise driving off rapidly. And you might want to disguise yourself. Above all, do not call a lock smith. That ruins the fun of being a do-it-yourselfer.

High security lock systems, no way to over-ride.

Price a locksmith visit then call the dealer and price a rear door triangular stationary glass which is usually fairly inexpensive.

I wouldn't recommend breaking one of the roll down windows as they are much more expensive.

If you are in US, you can simply bring proof of ownership to the dealer and order a new key. It will take a couple of days to get new keys.

Yes, this is in US.....I'll go that route if need be......thanks.

It is always safer to have more than one key, and they are kept by separate person (if that is possible).

BTW, how did you manage to lock the door? MB always needs key/remote to lock from outside. If you lock from inside, all doors unlock the moment either front door (or driver door for cars earlier than mid 80s) is open. Connecting to battery power itself does not trigger locking action.

Doobie brother wrote:

we bought the car used......never had 2 keys. the car was unlocked when troubleshooting engine surging at idle....figured it wouldn't hurt to reboot computer....got out, leaving key in ignition, and removed batt cable.....five minutes later I go to reconnect and pop, pop, pop ....the doors lock!!! and the horn beeped a few times!!!

I have a locksmith coming out to open it up tomorrow, but I'm convinced if one knew just where the door lock wires are under the hood, it could be unlocked.......................

No... no door wire in the engine compartment. It is much cheaper to get a duplicate key from dealer.

I suspect you might have an aftermarket alarm system or keyless system installed in your car. Only alarm will lock the door when you turn on ignition.

Actually that should no longer be true. As of 10/01/2008 Mercedes-Benz USA sent a Bulliten to all their Dealers with new mandatory security proceedures for all TRP's (Theft Related Parts).

Keys for lockouts etc may be ordered from the dealer in person by the current registered owner only and original documents must be presented, copied by the Dealer and retained at the Dealer for 10 years and subject to audit by MBUSA on request.

Further, Ordered keys may ONLY be installed or surrendered to the actual vehicle owner with the vehicle present in the dealers shop and a Repair Order opened to document the Dealers compliance with the new policy.

This new policy strictly prohibits the Dealer from simply ordering replacement or spare keys for clients and handing them accross the counter.

Um, like Tiger says, I feel it is aftermarket too. MB alarm does not work this way. I don't recall the horn ever sounds when MB system is armed. I have an 89 300TE with aftermarket alarm. Shortly after buying the car, I disconnected the alarm. I prefer the factory one. Of course, no instruction/wiring diagram on the aftermarket system also worried me. I had a similar experience (but not as bad as yours) from a different car/make.

The MB central locking has the wiring and vacuum tube running inside the doors, under the carpet (passenger/right side near door frame), under/behind the rear seat. There is no wires under the hood.

Doobie brother wrote:

OK everybody relax. I'm unlocked....I jacked up the front end, drilled 1" hole in floor pan, slit carpet, pushed up lock button with long rod, welded up floor pan...it took a total of 40 minutes.

Gee instead of welding up the hole you should have plugged it for the next time.

By the way having keys locked in your car is usually covered under the emergency road service/towing coverage with your insurance policy.