I have a 1997 E320 which had some kind of problem with its security mechanich. Initially Remote would not unlock car, I had to enter the car using the front passenger door lock which I've replaced the battery in the remote. Now the remote can open the door but not re sync to car so it doesnot start the car.
When remote is pressed lights on rear view mirror go from red to green and start flashing. When using key in passenger lock only that door will unlock. I've tried the re sync procedure (press remote 2X(car lock & unlock) then place in ignition and start vehicle) many times, checked all fuses under rear seat and hood, but still it won't re-sync and start.
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THIS IS A RESOURCE I 1ST TRIED OUT WHEN I 1ST MOVED INTO MY HOUSE, SOME IDIOT HAD THE GARAGE DOOR TENSION REALLY SCREWED UP....I WAS ABLE TO "HOW TO ADJUST A GARAGE DOOR" AND SAVED MYSELF A GOOD $150, KEEPING THE REPAIRMAN AWAY. YOU CAN "HOW TO" ANYTHING, AND 99% OF THE TIME FIND AN ANSWER