Mercedes S320 central lock

What happens when you turn the key? Do the door locks work? Do the headlights work? Once I get that info I can help point you in the right direction

hi, if any doors, boot or bonnet is open it will not lock. there are SWITCHES that has to be set.for the system to recognize it is closed. please check all openings even windows. ONLY DO THIS IF.if the BATTERY HAS BEEN TAKEN OFF OR BATTERY HAS BEEN DISCONNECTED. the SYSTEM MAY NEED RESETTING. the battery NEGATIVE lead needs to be taken OFF and place the NEGATIVE LEAD ON THE TERMINAL (A NOISE WILL BE HEARD), the ALARM and CENTRAL LOCKING SHOULD BE RESET, if the ALARM DO'NT SOUND put the lead ON and OFF a FEW TIMES. CLAMP THE BATTERY LEAD CONNECTION TIGHT and press the ALARM BUTTON OFF and retry locking SYSTEM. this will work if everything is O. K. gerry

Isn't there botton somewere on the door or left lower conner of dashboard to open trank remotely?

The locking system is controlled by vacuum . It is really hard to figure out because there are so many things that need to be checked. You can look for broken vacuum hose under the hood. Or under the dash. There are vacuum controls in the doors. Theres a vacuum canister in the trunk. Good luck This may help some. Leave comment.

Synchronization
Turn ignition switch to position II. Turn ignition switch to position 0 and remove key. Within 1 minute: Press and hold key lock button. Press unlock button 5 times. Remote control should now operate system. If not: Repeat procedure.
Programming
When
Key remote control added or replaced. System malfunction.
How
Keys can only be programmed using diagnostic equipment.
NOTE this only works on ml up to 05

sounds like you have a wiring problem in the main lock switch in the driver side door or wires that run from there to the other doors. one of the wires in this system does not have a good enough connection to allow enough current to operate the locks. put another way, the wire itself is introducing unwanted resistance which reduces the current flow. the resistance could be a result of a poor connection at a junction or a section of wire which has corrosion or some other problem which diminishes flow. to find exactly where the problem lies will involve removing door inner panels and making voltage drop tests across connections. works something like this: i started out with 12v dc, i know this component should use 3.4 v (or whatever it is) but now i only have 4 v coming to this next component. so the wire is using some of the voltage. some drop in the wire is normal, but not very much. that is how i would troubleshoot it. you can just check the connections to power and ground, just look at things and make sure you don't see corrosion, wiggle connections and see if it makes something different happen, but you will still have to take the doors apart to do it. hope that helps

You`ve obviously got two problems with ur vehicle,

You need to get a diagnostic readout on the various systems which are being displayed on ur dashboard. If youve been disconnecting the battery, these lights will appear because the steering angle sensor will need setting.

The fact that ur key dont turn could be a few things

Firstly the key, have you got a spare to try? If u havent then get one

Secondly It could be the EIS switch itself, I change loads!

Good luck!!
Carlo@SS

There is a central door locking pump under the back seat, the motor has gone in it, cheap way to repair is to strip it down and put a motor in it from a tyre compreser from argos for under £10 very easy to fit just two wires

just insert the key to the ignition swich and leave it for one minute, it will work for sure.
Adel

leave ign off with key out 3mins disconnet battery 5 mins reconnett and press lock/ unlock repeatedly until locks cycle through to re sync try this any probs come back to me