1992 300SD W140
My alarm system won't disarm unless I pull the fuses.

When I pull the fuses and reinsert them the light in the doors/trunk flash green. Then if I lock any of tehm the light flashes red and ONLY the loack for that door/trunk will lock. the others remain in the postion they were in. then if I open the door or trunk the alarm goes off. If I try to reset the door or trunk i.e. close the trunk or door and relock it the alrm keeps going.

I have recently installed an aftermarket stereo , 2 weesk ago ) but the alram and door locks have be opperating fine.

I do know if you get out of synch i.e. arm the system or disarm the system froma different door it will set off the alarm adn you to go around and find which door weas last used!!!!! Thats why I disabled my alarm on my old W126!!

I would be happy with the alram disabled (I personnely think alarms are stupid and annoying!!!!!!!!) as long as the infared remote locking (all doors at once) would dsill work!!!!!!

BTW all this has been done using a TRUE master key. New form MBZ.

Also does any one have the wiring diagrams for the alarm system from ETM?

Thanks in advance!!!!!!!!!!!!

Steve
email: stevenwkee@rogers. com

MOre info:

When I reinsert the fuses back, the all 3 lights flash green.
If I open a door or the trunk the alarm goes off with the lights flashing green..

Question:

I have the radio alrm disconnected and not touching anything. Waht should this be connected too?

I have had my aftermarket radio in for about 2-3 weeks with no problems being like this. Should it be connected to ground?

Thanks
Steve

I am no pro but here is my 2 cents...

behind the radio, there is 1 wire with a metal clip that plug into your original Becker system. This wire is an alarm wire which when unpluged (if the car is arm) the alarm will go-off. It looks for a constand "ground" signal and when the signal is broken off, i.e. unpluged, the alarm will go off.

Just re-connect that wire to some ground source. However I know that in the early models, if the wire is getting no ground before the alarm was arm, the alarm system is smart enough to ignore that wire. Anyway, just try connecting that wire back to some ground source first.

never heard of this... what are you on about. As far as I know the alarm on the 140 can be arm and dis-arm from either doors or the trunk.

here is my question, if you get to solve yours I hope you can solve mine too.

All aftermarket alarm have a by-pass switch which allows you to bypass the thing if the alarm go crazy. i.e. start the car even if the alarm is going off as long as you can find the switch and turn it on.

Does 140 have similar? I am worried if the alarm goes crazy one day and I have no choice but to tow it even with 3 metal keys on me.

if someone can share lights, please do!

BTW, which fuse did u unplug to reset the system!

I tried grounding the connecter all ready.

WHen reinsert the fuses I belive they are #2 - 7.5 amps and #15-25 amps in the REAR fuses compartment ion the trunk. #15 ( the 25 amp one ) silences the horn. IF I leave in the 7.5A fuse I can use the inside drivers door lock button.

MY car will start with the alarm sounding!?? \

ALso the when I repower the alarm system the lights "Flash" green and when I open any door or the trunk the alrm goes off.

Sounds to me that the brains are stuck ALWAYS ON or a switch is constantly on. the flashing green light is what bugs me!
Also when I lock any door or trunk the light flashes red. It does NOT turn green when I UNLOCK the system.?????

since it sounds like this could be attributable to your aftermarket install,take this question to the audio section and seek help from a guy that goes by the name SCLJA.i'd think he'd be able to get you on your way

__________________
'95 s500 (bought for wife but can't bear to share!!!) 125kms
'92 legend 180kms
'88 tbirdturbo(fantastic car-only regular maint.)120kms
'87 mustang gt(gone)
'86 tbirdturbo(gone)
'85 mustang gt(gone-but not forgotten)

Check this website LOTS OF GOOD INFO for the W140

http://pages.prodigy.net/jforgione/MB_S500.html

I did post it to the Audio forum, thanks Scott form La Jolla Audio is VERY helpful. He helpped withteh stereo setup/install I did.

what it puzzling me is that the radio has been in for 2-3 weeks with no problem.. ?? go figure!!

I will get a scanner todaya and look at the codes for the alarm system ( ATA).

thanks
Steve

No the W140 doesn't have one as far as I know. defeats the purpose..... MBZ would never do that ;-)

I will make a scanner today and read the codes in the ATA.

Steve

right....

but the thing is... I can't start the car if the alarm is on. It won't even crack....

If yours start... i think your system have some real problems... unless my car is setup differently...

what about others.. does your W140 start when the alarm goes off??? If so... do your have a contingency plan?

92 W140 did not have starter circuitry connected to alarm. Only 93+ model years did.

Does any have the electrical diagram for a 1992 W140 Alarm aka Anti Theft Alarm-ATA?

I am searching ebay etc. and I am hopeing to get an ETM etc soon.

thanks in Advance
Steve