Just bought my 91 sl and the interior lights don’t come on when I open the drivers door,I tried pushing in the door jam switch but nothing happens
when I open the passenger door both door lights and interior lights come on. Just nothing with the drivers door. Any ideas what to check

 

Yes.

Pull and inspect the driver's side switch to make sure it works.

 

I have the identical problem on my 1990 SL. I've checked the door switch and it is working correctly. I've had two independent shops look at it but neither one has a clue re. how to repair it.
Maybe someone will see this thread that knows where the problem lies.

 

replace the left dome light switch

 

The left dome light switch works as it should when you push the buttons to turn it on/off. The problem that the OP and I are both having is that when you open the left door (without opening the passenger door, none of the lights come one. If you open the passenger door, the correct lights come on and if you walk over and open the driver's door, those lights come on exactly as they should. If you leave the driver's door open while the passenger door is open and then close the passenger door, the driver's side lights immediately turn off.

 

You are experiencing a poor/bad connection from the LF SAM module. power is not getting from the door switch to the SAM to the door.

 

1,What does SAM stand for?
2. Please tell us where the LF SAM module is located.
3. Since the lights will turn on in driver's door if the passenger door is opened, are there two wires on each door that go to this module?
Thank you for your help.