On 1994 mercedes benz s320 central locking will not work by key or dash switchhave checked the fuses i can find,when door key is turned pump under rear seat works for about 10 seconds any clues where to look next

check your fuses under the dash and under the hood

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

maybe you have to change the
Mercedes W140 Central Door Lock Vacuum Pump

You may have two separate issues here. First as for the brake lights not working I'm guessing they all went out at once. If so there is stop lamp switch located on the arm of the brake pedal. If this switch stopped working then you will not have any brake lights. The panel underneath the dash has to be pulled out in order to see the switch. As for the locks not working the pnuematic pump which supplies vacuum for the central locking to work may have either quit working or shut down due to a vacuum leak in one of the vacuum elements. To check this go to the fuse panel in the trunk and look for the fuse for central locking and remove it for a few seconds and re insert. This will reset the pump and allow it to work again. Try the locks a few times to see if they are working. If they don't work right away then you may have a bad vacuum pump for the central locking. The central locking pump is located under the rear seat cushion on the passenger side. Hope this info helps you out if not let me know and I will try to do what I can to assist you.

seems to be faulty centerlocking pump which is under the right rear seat, remove rear seat cushion then have look at right there is center locking pump, it has coverd by sponge box, open sponge box and remove wiring socket from pump and install fuse then have a look, if fuse not blow now faulty pump, replace pump, if fuse still blowing could be wiring short circuit from some where, need to be diagnose, is this information helped you, i am from New Zealand too. have a good labour week end,

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

Central locking fuse or pnuematic pump under rear seat has gone bad.

Sounds like your pneumatic pump has failed or the fuse has blown. There is no reset per say. Contact dealer for replacement owners manual or ebay.

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

if you hav a remote control key &yr car wont respond . change key batrrey &contact dealer if still dont work for software