The warning module/seatbelt reminder has 8 pins. I don't know if the '89 model w126 has a different part #. It's right beside the cruise control module which is a much bigger box. I found that it's the easiest to pop the old module/relay out of it's "box" or housing instead of trying to remove the screw on it's bracket. Then you can just pop in the new module in the old housing. It's saves you the grief of removing the cruise control module and bracket. It's a real pain to put it back up there. Good Luck.

Nolan