Hello: I just received by mail a keyless entry that was bought by the previous owner of my 1991 500SL. I know it is the correct unit for the car because the physical key fits and works find in the ingition, trunk, etc. but I would like to know how to program the wireless portion for remote locking/unlocking. He had ordered the new remote but had not yet received it by the time I picked the car up so it was not programmed when I got it. Thanks in advance for any help on this.

Mike
First make sure the battery is OK by pushing the button and look at the red lense, after about 5 seconds you should see a short red flash, which indicates the battery is OK.
The instructions for synchronizing the remote should be in the owners manual, it cvaries a little from year to year, so not sure I can give an accurate answer, but of course you'd want to make sure the battert is OK.
Gilly

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Gilly:

Thanks for the reply, I should have mentioned that I did install new batteries and get a red light on the remote. The manual says to point the remote at one of the receivers by the locks and send a signal, then to unlock or lock the door within 30 seconds using the master key. None of that worked so I guess I have to assume there is something wrong on the vehicle side with the system. Someone told me that when I send a signal to the receiving unit that there should be a light that flashes back, but I don't see that, again suggesting something on the vehicle side, but I have no idea what.

I thought usually it went like this: Put key in ignition, turn key to "on" (not start, the click just before start), then you remove the key and I think it's either A) aim key at receiver on door and press button, or B) put key in door lock and lock/unlock (more leaning towards A). Is the owners manual correct for the car (same year)?
Is it possible someone installed the proper metal blade into an eBay remote? The blades can be replaced, in case a blade is broken or worn out, so you could have a "Frankenstein" key.
Gilly

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i have this sheet that i was given when i was at the dealer. this is the official programming instructions.
hope this helps. please let me know how it works
Ray
Mercedessd@cox.net



Key synchronization Procedures

SL Models
90-95 see note 1
96 see note 3
97 see note 2
98-99 see note 4

S-Class Models
92-95 see note 1
96 see note 3
97 see note 2
98-99 see note 4

C-Class, CLK, E-Class
96 See note 3
97 See note 2
98 –99 see note 7

SLK

See note 4

M-Class

Early 98 Models up to A010609
With original AAM and keys see note 5

Later models 98-99 after A010609 see note 6

Note: All M-Class keys require the HHT for Initial Installation

Note 1: Aim transmitter at a receiver and briefly press any transmit button. Within 30 seconds, lock or unlock car at a door or trunk with the new master key.

Note 2: Aim transmitter at a receiver and briefly press the transmit button twice. Within 30 seconds, insert new key in steering lock and turn to position 2.

Note 3: Aim transmitter at inside rear view mirror receiver and briefly press transmit button twice. Within 30 seconds, insert key in the steering lock and turn to position 2.

Note 4: Aim transmitter at vehicle and briefly press the lock or unlock transmit button twice. Within 30 seconds, insert key in steering lock and turn to position 2.

Note 5: Turn key in steering lock to position 2, then to position 0 and remove. Within 60 seconds, push and hold the lock button for 15 seconds, now push unlock button 5 times. Then check all functions.

Note 6: turn key in steering lock to position 2, then to position 0 and remove. Within 60 seconds, press the lock and tailgate buttons simultaneously for 15 seconds.

Note 7: For Smart key equipped vehicles, simply insert key in the ignition switch and follow info in the cluster display

Since I bought the car second hand the second remote never worked. It worked in the locks as a key, but the remote wouldn't open the doors. The light in the remote goes on when pressing the button, but thats it. I tried the above instructions on my 1997 e300d aiming at the rear view mirror receiver, and it did not work.. Thanks anyway tho... Indy