2002 Mercedes C230

Installed a Firstech Compustar into a 2003 Mercedes C230. The install went well exept the door locks, and light flash. DEI tech notes indicated the right tag, and it tested correctly, but when connected to the alarm....No Go! Tested for a negative multiplex system and found in fact there seemed to be. Applied the correct resistor but once again no go. If you have succesfully added light flash and lock interface please drop me a note! Thanks in advance.

this is the info i have for the 2002 c class. not sure if it will help. Parking Lamp GRAY / YELLOW (+) AT HEADLIGHT SWITCH Power Lock BLACK DRIVER'S KICK #201 Power Unlock BLUE PANEL #201 - See Negative Pulse Door Lock DiagramGood Luck

David

Ace Security

813-376-9778

Tampa

Donate to the 12volt

I usually don't use the tech notes. I take a voltmeter and I check the wires by myself.It takes a bit longer but it is 100% sure. Try to play with the power locks and listen for the relay. Then usually the control wires (75% or them) are thinner than the rest. Try to connect the black cable of the voltmeter to ground and the red one on the wire. It can show +12V or nothing. Then play with the power lock and see if the +12V will drop for a second then you found it and it must be a negative activated system.If you get a +12V for a split second then it is a positive activated system. As for the lights I just open the steering wheel column and find the wire there. A bit more work but as I said 100% sure. In Europe we use the turn signals and if you want to use this it is pretty easy to find the rellays. Good luck and let us know if the info was of any help.

Thanks for you input! I have found the correct connection points for the alarm. red (unlock) black (lock) at the lock controll module in the drivers door. It tests negative trip but will not lock and unlock the doors (even with a direct connection to ground. I cut the unlock wire and tested for resistance whick I found (15K) but even when I used the correct resistor in line the locks would not trip. I also found the park light controll wire at the light switch which is easily accesable through the front fuse access panel on the drivers side on the vehicle. This also tested 12v but would not trip from the alarm. I have not found any installers that have actuly put an alarm into this vehicle succesfully. If you have PLEASE drop me a note.