93 190e code reading question.......

[240diowa]

Have a 93 190e 2.3 L and I want to read the codes. I have the 8 pin box by the battery with the led by the #2 pin location. When I turn the key to the on position the led is steadily lit, I press the button for 3-4 seconds and it is still lit. Need some guidance on how to do this correctly