| Re: 99 sls drive door lock/keyless entry
You have 2 problems:
1. The driver’s door lock (probably the actuator is busted or you have a harness issue)
2. The key fob contacts for the lock/unlock/trunk buttons are gone.
To fix 1 you need to start from the driver’s door actuator al the way to the PZM.
To fix 2, could be as simple as opening the key fob, take the PCB out (separate the PCB from the rubber mat with the buttons) and clean with a Q-tip and alcohol the PCB area that faces the buttons. You can also clean the rubber contacts (behind each button) but do not apply pressure to wipe out the graphite (clean ONLY if required).
If no worky the find some other remote not necessarily the same part number, all you care is to have the EXACTLY same buttons (so you can use the rubber mat on your remote). When looking for a “parts” remote make sure the symbols on the buttons are not wiped. That is a tale-tale sign of possibly bad contacts (since the button symbols are wiped imagine hoe many time was used!).
If you swap the buttons (the rubber mat) and you keep the PCB you don’t need to reprogram your remote. | 
