I have an SL500 (1995) I cannot get the remote to work. I have changed the batteries on the remote and synchronizing, not a peep!!
Any ideas on what else I can try?

Try pointing the remote at the rear view mirror through the wind screen.

Otherwise I believe there is a re sync proceadure? Someone can confirm

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1985 190E - Gone
1989 230E - Gone
1995 C200 - Gone
1993 280E 120000KM - Built like a brick, the best one yet

Thanks for the advice, my SL has the alarm pickup in the rearview mirror (green and red) this works well. The sensors are next to the door and boot locks I have tried pointing at these and syncronising without sucess.

There's a telltale LED on the remote located behind the red lens. Press and hold the button and make sure the LED illuminates. That confirms that the remote is working.

I assume the remote is original to the car? If just replaced it by purchasing one from eBay (like I did more than once), your money is gone - the remotes are paired with the car, and can only come from the dealer. They use the VIN of the car to know which "frequency" of remote is the correct one.

If the remote is original, and you see the telltale LED - verify your synching method - this is what you should have done: Aim transmitter at receiver, briefly press button. Within 30 seconds, lock or unlock the car with a master key (can be the key on the remote). It seems like I've also seen where you might need to lock and unlock repeatedly...

If you've tried this on the driver's door with no positive results, try it on the passenger door - the synch process works there, too.

If still no positive results, it's possible the keyless entry module in the trunk is kaput. This is the device that's paired to the remote, so be sure to get this from the dealer, after making a substantial withdrawal from your bank...

If this turns-out to be the case, I would consider going with an aftermarket keyless entry system. They are simple to install, inexpensive, and have long range due to their radio-frequency operation. I plan to add one to a 1991 500SL.

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I had a similar experience on my 97 E-320, and after searching the owner's manual, there was a simple procedure to follow to re-program the remote. I followed the instructions and my remote worked perfectly after that time.

Thanks for the advise, the remotes are origonal, I have had them recoded at the agent. I have held the button in and the red light comes on. I have synchronized by aiming atthe door and turning the ignition on.
It looks like I need to buy the after market receiver.