83 240D I was working on my passenger side window switches/motors and vacuum switch for the pass side door lock yesterday. This morning the trunk wouldnt open. Someone once mentioned an unlock release inside car but I dont have owners manual.
Besides non tech reasons such as lock jammed, key messed up. are there any technical reasons, related either to paragraph above or other

There is no inside the car trunk lock release. I suggest you take out the front passenger carpet, pull up the plastic under which the vac. lines run. There you will find rubber fittings that can be disconnected. One of the lines going to the back of the car will be for the trunk lock, try putting vac on it.

Also, you should be able to unlock the trunk by putting the key in the lock and turning it to where there is spring resistance, then continue turning until it hits a stop. While the key is in this position, push in on the release button for the trunk.

If this does not work, the only remedy left is to drill a small hole through the panel on which the license plate is fastened. This would be drilled directly below the lock assembly. Once this is done one can insert a stiff piece of wire into the hole and press against the lock release. Have done this on several as a last effort.

Bob

Before drilling any holes you can try to access the trunk by removing the first aid kit (if you have one, my '83 300D does) on the rear deck.

I don't think drilling is a good alternative. It might sound simple but saturate the lock with WD-40 by pushing the inlet where the key goes in. If that does not work. I heard there is a wire but it is under the driver's seat not, sure on this one though. Exhaust all alternative before drilling including, going to the dealer or indepedent mech.

Thanks everyone! Nothing is in my trunk, but it just
p_s me off. After all I brag my 83 240D is used as aTaxicab inGermany and is more reliable than half of (the non Mercedes) brandnew cars sold today.

rbdrost has your solution:

"Also, you should be able to unlock the trunk by putting the key in the lock and turning it to where there is spring resistance, then continue turning until it hits a stop. While the key is in this position, push in on the release button for the trunk.

On my car, you have to put the key in, turn it all the way left, and while still holding it there, push in on the lock button. I'd be very surprised if this didn't work for you...

This is part of the vacuum locking system on these cars. Your fuel door is the one with the inside release, and that's in the trunk. You might check that out before you're at a fueling station, and can't open the fuel door.

__________________

Scott Longston
Northern California Wine Country...
"Turbos whistle, grapes wine..."

Glad to see you received lots of response - most saying do not drill. Sometimes it is necessary to get drastic - I did not see any alternatives to drilling in a situation in which neither the key or the vac. lock does not release the trunk, even after WD-40 fails.

The reason it is necessary to drill is because both the vac. element and the push-button release the trunk release mechanism by pressing against the catch. Sometimes, in particular on the 240 or 220, due to wear, the release mechanism does not fully engage the catch that is keeping the trunk from releasing. I suspect your vac. system may be working alright if neither that or the key will permit the catch to release.

If it becomes necessary to drill, it is best if you look at the mechanism on another 240 or 300 first to determine where to drill. The location of the hole needs to be about 1 1/2 inches directly beneath the location of the catch and can be about a 1/8" hole. Push a piece of stiff wire (coat hanger) through the hole and you will be pushing on the lower part of the catch - if you are at the correct place, a good push will release the catch.

Good luck

Bob

One last comment - taking out the first aid kit will not help, there is a metal panel under it. Even if there were not, one could not get at the catch mechanism.

The required small hole does not result in disaster - simply plug it with a little caulk and wipe off the excess - "only you will know".

Bob

Hi there,

I also had to resort to the drilling trick on my wife's '74 280C - the vacuum portion of the lock failed and stuck in the wrong position. Since the hole is under the license plate, it won't show at all, and I just filled it with some silicon sealer. With my wife's car, there were two keys, one that operated the ignition, doors and the trunk, and another that only operates the ignition and doors. Perhaps you have the same scenario? Just a thought...
Richard Wooldridge
'82 300D/4.3LV6
'74 280C
'77 280Z
'77 Jag XJ6L