First, i need to make sure that both of your sunroofs are the type that run straight back into the roof. To get the headliner down you need to get the roof to slide back a little bit (or all the way) and then grab the lip in the front and force it to pop down, it is held in by snaps. Once you have pulled it loose you need to slid it foward and bend it so that it can fit out of hole for the sunroof. This will expose the clip and the inside of the roof. You will see a metal guide that the cable runs into that runs down the roof. The guide ends right where the clip is and the cable just starts to pop out there and the cable then connects to the small clip. Check that connection and check the clip, once you have done this let me know where you both stand. First look at the clip and the connection between the cable and the clip.
1986 Euro Black Metallic 190E 2.3 16V