Stephen C. Greenwell

I saw that but I'm starting to think that I have the 'without' version. It does have OnStar controls to answers you question though Sent from my iPhone using Tapatalk

I purchased the truck with it already installed but from the back of the mirror it is a Gentex and from the website seems to be the '50-GENK356A'. I don't know if your instructions would work but it's worth a shot. If it's a hassle to dig out don't worry about it. I've looked everywhere online and can't find anything that says that it should or should not have guidelines. Thanks for your suggested help though. Sent from my iPhone using Tapatalk

How did you get the guidelines to turn on? I can't figure that out for the life of me! Any help would be awesome!