I HAVE '97 E320 W INFRARED POWER LOCK SYSTEM. THIS MORNING I COULDN'T UNLOCK THE CAR FROM THE DRIVER'S SIDE. WHEN I WENT TO THE TRUNK, WHERE THERE IS ANOTHER INFRARED SENSOR IT UNLOCKED. WHAT DO I HAVE TO CHANGE ? JUST THE SENSEOR ON THE DOOR /RED-GREEN WINDOW/ OR THERE IS SOMETHING ELSE ???
PS DO THESE CARS BRAKE SO OFTEN ? I CONSTANTLY HAVE TO FIX SOMETHING !

You should try to change the battery first. I have a 99 E430. I can tell you the range on the remote is the worse I have seen. Sometimes I have to walk right up to the door to unlock it.

But in your case, I don't think is the infrared sensor because the remote would transmit duplicate signal in the forms of radio frequency and infrared. I am not sure if your remote can open windows. If your remote does open window, according to owner's manual the remote only transmits in infrared. So to test you door infrared sensor, you can try to open the window using the remote.


Hope this help.
Car Nut
99 E430 Sport

I know what you mean...
 

You practically need a laser sight to correctly aim the infrafred remote at the sensor, particularly if you are standing on the passenger side of the car trying to hit the mirror-mounted sensor. Finally for 2001 model year MB changed to radio transmittor remotes like the rest of the civilised world.