I just realized this, when looking in my repair manual. The map light for the navi model has a separator between (where the homelink goes). The non-navi (which I have) just has to lights that meet in the middle. This DIY is for navi models only, although I'm sure it's possible to replace the entire map light fixture for a navi, then install a homelink. I'm not sure how worth it that would be though. There are quite a few other ways to install garage door openers, although none are as clean as this.