central locking on 300sl

[markmerc]

Hello to all. Has anyone experienced this? I have a 1991 300 sl w129 I think. While operating the remote key/button the central locking does not work. After locking the doors manually with the key to secure the car, then opening the doors or starting with the key through the ignition , the alarm goes off. The car will start ok and is drivable, but the sounder operates and the hazards flash. Central locking does not work at all. I have recently had an MOT done as I live in England. I was wondering if the inertia seat belt / automatic door unlock has been operated,so disssabling the central locking? Is there a reset switch for this? If so could anyone tell me where it is?
Thanks, Mark.

 

[television]

your car has the same locking system as the 124, I am off to bed now, hard day tommorow, if no one comes back with anything I will go into it tommorow evening.

Malcolm

 

[markmerc]

Thanks for reply Malcom ,much appreciated!

 

[R129]

Hi

The locking on your car runs off an electrically powered vacuum pump which means that there are potentially two areas that could be at fault. The doors do unlock after an accident but this is automatically reset and there is no provision for manual resetting.

The pump is housed in the boot under the panel that covers the battery and is a black plastic box with yellow pipes attached.

The compete lack of locking suggests an electrical fault, this can be confirmed by listening for the motor operating when you lock the doors. No sound indicates a fault with the motor or the supply to it. There are switches in the locks that operate the locking when you use the key. If the motor runs it will likely be a vacuum fault.

With the operation of the alarm it is likely that it is an aftermarket fitment to comply with insurance requirements. In my experience almost all the aftermarket alarms I have seen fitted have been done so incorrectly and as it will have most likely been wired into the central locking system this could be a possible cause of the fault.

The simplest solution is to disarm with the remote and unlock with the key until you can get a competent specialist to look at it.

Good luck and let me know how you get on.

 

[MBFAN]

central locking

Just a quick note. Have had a similar problem with my 1992 300sl. I have currently disconnected the alarm system with the fuse under the passenger carpet. I bought the car without a remote, so was locking/unlocking with the key, the alarm fault started when the battery webt flat after going on holiday. I have since bought a remote from mercedes and central locking would work with remote to unlock only, not lock. I have found that the central locking solenoid pump on the petrol flap is sticking. I have disconnected this solenoid in the open position and blanked off the pipe, the central locking is now operating perfectly. Have you tried to reset the remote as described in the manual? Just recommected and retried the alarm but that is still not working correctly, but al least my central locking is operating. My alarm unit is a meta system if anyone has any idea about them?

 

[television]

Hello Mark central locking on 129's was not an option, it is standard.
as the remote is not unlokocking or locking the car, or unsetting the alarm, the first thing to check is the remote. You can do this with a digital camara or phone-camara, just hold the key lens in front of the camara, when you press the buttons the infra red beam can be seen. do this first.

Malcolm

 

[markmerc]

Thanks for the info boys! Apparently the alarm is factory fitted according to the manual. The remote looks ok, just nothing happens, no lights or noise. Looks like total loss of the central locking, which I imagine would be connected to the alarm. Hence the alarm operating. I have checked the fuses and they are all good. Will get in touch with my merc mechanic.
Thanks to all for throwing some light on the subject.
Mark.

 

[television]

Arming and disarming is all part of the central locking, once set with the key it can only unset with the key fob remote.
remote looking OK does not mean a thing, I have a box of 120 tv remotes, they all look like new, and that's where their use stops.

Malcolm

 

[markmerc]

Thanks for the info malcom. Sounds like you have an interesting collection of tv remotes.