IIRC there are two small Philips head screws under the home link unit. What I do not recall is if those screws are actually holding the entire assembly up or if they just hold the smaller unit to the assembly. Ether way I do remember gently prying to remove a small portion of the unit, undoing a couple screws and then gently prying to remove the rest of the unit. There is a third screw but I am 90% certain that it is just holding a sub assembly together and not the entire unit to the roof. If you don't have a set of plastic trim removal tools I would get one, best $13ish bucks ever spent.
Also the wiring to the switches is easy to remove but there is a central wiring harness that was a pain, I had to remove the actual wiring from a tie down to be able to clear enough space to get the plug out (will make sense once your in there).
I can get you more details this evening if you need. Also curious as to what you need to repair in there.