Fastrak Placement for 2016 MS

[hmmm]

I realize there are multiple threads on the topic, but I want to make one re. 2016 MS in particular since the windshields have evolved over time. I just got my new flex transponder and want to make sure I maximize my chances of "success".

Way back, I remember reading that it should be placed to the right of the rear view mirror, upside down for better results? Does that ring a bell? Also, any specific locations for the new flex vs. the older non-flex transponders?

Thanks

 

[Warbird]

I stuck my fastlane transponder on under underside of the rear parcel shelf. The velcro on the transponder sticks directly to the fabric. Works fine.

 

[Russell]

I registered my license plate to my FasTrack account so now I keep the transponder in my glovebox.
If I want to get a carpool discount then I will place the transponder on my dash just for that portion of the drive.

 

[coder]

I have the same question. I think the issue is specifically with the newer tags that you can set to 1, 2, or 3 people. We have ours in the top of the rear window. It works on 580 but only sometimes on 680.

Does anyone know if Model S before 2016 has a spot on the windshield where they didn't use metal?