W124 E200 diesel central lock/infrared problem.

[Fede]

Hello everyone.
First of all my name is Fede and wanted to thank you all for letting me be a member of this great group. I´ve been reading many of this forum´s threads since months ago but just as a guest.
I couldn´t find in any of the posts the exact failure this car is experiencing. I´m helping a neighbour who has a 1995 W124 E200 diesel with only 90K kms which is to be sold and has been sitting in her garage for a couple of years. I know someone had helped her charging the battery eventually and some extra work to keep it running but she couldn´t tell me exactly what they have touched to have a clue where to start.
Up to now, the car has new fully charged battery and new batteries for both remote controls since they were depleted. (car has infrared panel at drivers door with no lock and a boot panel too).
After testing them the way someone explained in other thread, remote controls work perfectly fine , but I couldn´t find the right way to pair them with the car (after following owners manual procedures and even those found in the web). Neither of the infrared panels respond. Lock/unlock mechanism works perfectly fine from the pushbutton in the center console.
On the other hand, and I think it might be related to previous paragraph, the car won´t even crank when turning the key. I guess it might be related to the immobiliser, which, by the way, I couldn´t find where it was supposed to be.
After trying many times with no particular pattern to match the keys, and even infrared system not responding at all, eventually the car starts.
I´m completely lost in this one and would really appreciate any help from you.
Thank you in advance.
Fede

 

[optimusprime]

Welcome Fede can you tell us what make the alarm is thats fitted to the car . If it was fitted by Mercedes from new you might stand a chance, but if it is aftermarket -= that is fitted by the owner,, or the garage ,,it was sold by ,, then you will have problems.

 

[Fede]

Hi Optimus!
Thanks for your reply.
Seems that it has a Mercedes alarm. There are no signs of having anything extra fitted.

 

[optimusprime]

Fede if this may help you ,,,i dont know but it is worth a try .This free W124 workshop manual we all have as a few bits of information in the back on the factory fit mb alarm.You need to google this Model 124 Maintenance Manual Index

 

[Fede]

I will google it. Hopefully I can find the answer there.
Thanks for your kind help!

 

[219]

Do the keys have a little red dot on them ? That denotes a factory alarm system .

 

[Fede]

Hi! Sorry I didn’t read before. Keys are quite worn actually, but I’ll check.
I’ll keep you updated.
Thanks!

 

[Benzowner]

Did the early W124's come with an alarm? I bought a 260E in 1989 ish and I am sure I had to have an alarm fitted, the car was not supplied with a radio back then, it was extra, so not so sure an alarm would have been included.

 

[Fede]

Hi Geoff.
This one is 1995 and I’m not sure about the alarm it has. What I do know is that it hasn’t the ATA on the passenger side floor. Also found the infrared controller beside the central lock system below the rear seat.
I’m guessing, based on what I could find here, that may be a relay problem since I find little chances that both drivers door and boot infrared sensors would fail at the same time. I’m going to check if this infrared controller receives power. If not, may be a relay (hopefully).