Mercedes-Benz 600 SEL 1993 Owner's Manual page 32

"
3 Receiver next to trunk lock
30
Locking:
Aim transmitter eye (2) at a
receiver (3) and press transmit
button (1). Distance to receiver
max. 20 ft (6 m).
The red indicator lamp on the
receiver should blink. It stops
blinking after approximately
3 seconds when the vehicle is
properly locked.
P76-0025-1
Notes:
If a door or the trunk is not prop­
erly closed after you attempt to
lock the car by remote control, the
red indicator lamp will continue to
blink (max. 10 seconds). Open the
door or trunk lid, close it properly,
and lock the car again.
If the vehicle cannot be locked or
unlocked by pressing the transmit
button (1), then it may be neces­
sary to change the batteries in the
transmitter (If ok, battery indicator
lamp in transmitter will light briefly
when transmitting.) or to synchro­
nize the system, see Remote
Control, Infrared in Index.