Hey guys, my E320 has had alarm issues ever since I bought it and I'm trying to get to the root of the cause.
The car was imported from Belgium and is a 1995 E320 Cabriolet Sportline with a factory fitted Gemel Alarm system, this system has the part number 202 820 50 26, which tells me its shared with the C-Class. The car won't start under normal conditions, I have to unlock the car with the fob and leave the door open and wait for 2 clicks to come from the passenger floorboard where the gemel module is. If I disconnect the module and bypass the immboilizer relay the car won't turn over. If I don't hear the 2 clicks from the module the car won't turn over. If the car is unlocked and sits for longer than 20 sec and a door is opened, the alarm goes off, even if the key is in the ignition. If the car is unlocked from the passenger side with the key and not the fob, the alarm still goes off. I've replaced the module, both door switches, the hood switch, the car batter, key fob batteries, the radio with a stock radio. This also seems to be draining my battery but I'm not totally sure of that yet. The car acts completely normal when locked and all the vacuums for the locks seems to work fine. When I shut off the car, get out and close the door, the blinkers flash once as if it automatically locked, yet the car remains unlocked.
Any ideas?
that alarm with the remote fobs wasn't used in the USA, and we have no schematics to it. The instructions re disconnecting and jumpering the immobilizer relay are specific to the Becker alarm used on US models.
I can possibly shed some light on this as my first V12 W140 had this same alarm system.
First off, the Pentistar/Gemel alarm system was sold as an official MB dealer installed accessory in France as well as a independent offering. If your key fob has the MB star and you have the official MB booklet then you have the accessory version. If you have the black and red keyfob and/or no MB manual then it is most likely the independent version.
The bad. Pentistar went bust a long time ago, and functional replacement parts are almost impossible to come by. Even through MB if you have the accessory version.
In addition, this alarm usually was installed as a supplement to the factory installed version which also has it share of issues.
The good. IF you have the MB dealer installed version, chances are it was installed relatively cleanly and you can yank the whole thing out. That is what I ended up doing even though my system is/was fully functional up to the day I pulled it. The reason for pulling was 2 fold. No additional key fobs to be had and didn't want to live the day that system went boobs up and left my stranded somewhere.
Also, pulling the entire system stopped the battery drain. However, it is a pretty invasive effort requiring pulling wiring from trunk to engine compartment and everywhere in between.
Thank you so much! This is what I was looking for. I do have the original mercedes key fob which tells me that this is the accessory version. When you pulled the system did you have rewire anything? I can't seem to find the original becker module anywhere in the car. When I unplug the module it doesn't allow the car to start, so removing all the wiring for the alarm will allow the car to start?
On mine, the module was located in the trunk close to the battery. However, on a W124 that location might be elsewhere. Most likely place would be passenger footwell behind the metal plate.
On mine, the module was located in the trunk close to the battery. However, on a W124 that location might be elsewhere. Most likely place would be passenger footwell behind the metal plate.
you mentioned the immobilizer before... Assuming it works like the late ATA version, you can't just unplug those, you have to find the starter circuit and jumper it to bypass the immobilizer relay. since I don't have access to a wiring diagram for your alarm system, I have no idea how you'd do this.
It utilizes the same relay behind the instrument cluster like the USA version W124's, I've already bypassed the immobilizer by jumping those two pins but I still can't start the car unless the Gemel module clicks twice.
does the engine crank over with the immobilizer jumpered? if it does, but the engine still doesn't start, then that Gemel has some OTHER sort of immobilizer, such as a fuel pump disabler.
No, the engine does not crank at all. When the immobilizer is bypassed it won't crank unless the gemel module clicks twice, which I assume is relays within the module allowing power to get to the starter. If the module is unplugged it will not crank, regardless of the immobilizer being bypassed.
then either there's ANOTHER immobilizer relay, or you didn't bypass it correctly. the starter control circuit goes like, battery+ to ignition switch, starter output to immobilizer relay, relay to starter solenoid.
I think there's another relay within the control module, I definitely jumped the relay behind the instrument cluster correctly, copper wire wrapped around the two pins. The other post about removing the alarm system completely is more likely what I'm about to do; I'm just curious as to if the car will crank later on, since it doesn't crank when the module is disconnected and the immobilizer bypassed.
huh, I dunno much french but I'll be darned if I see any sort of starter disabler/immobilizer circuit on there. pretty sure Starter Motor is démarreur in Francais...
I do see fuel pump disabling. to remove this alarm, you'd need to find the half dozen wires they cut (couper, coupure), and splice them back together.
Unfortunately I do not think this is my alarm system. I looked up what the GR40 M2 module looked like and compared it to my module (the left one in the picture I posted earlier) and they looked completely different.
huh, I dunno much french but I'll be darned if I see any sort of starter disabler/immobilizer circuit on there. pretty sure Starter Motor is démarreur in Francais...
I do see fuel pump disabling. to remove this alarm, you'd need to find the half dozen wires they cut (couper, coupure), and splice them back together.
So I finally managed to get a hold of my Mercedes Mechanic and we spent the day ripping out the alarm system. This one was installed by the dealership in Belgium and was alongside the original alarm system, which for me was located underneath the rear passenger seat, next to the seat belt extender control module. It took us about 3 hours to remove all the wiring which goes from the fuse box to under the drivers dash, through the center console, underneath the passenger floor, and towards the trunk. This seems to have stopped my battery drain issue. I also managed to figure out why bypassing the immobilizer didn't work, apparently when they install this alarm at the dealer, the hot wire for ignition is severed at the fuse box and rerouted through the new alarm module. Removing the module and reconnecting this wire allows me to start my car all the time now. For those who have this alarm, removing it does not affect the car in any way, no lights get triggered, key fob still works the same. Hope this post helps anybody else who gets stuck on this issue.
Also the car is significantly lighter now that I removed the control module and what seemed to be 1km of wires.
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