Advice for FastPass transponder placement....Model S Refresh

[JPP]

I am also in Southern California. I have tried both styles of transponder (larger square version and the newer rectangular version with the 3-position switch), with no success thus far. I have a 2016 refreshed Model S similar to the OP. I have tried multiple orientations in the black area to the right of the mirror. The only orientation that I have yet to try is upside down - I will try that on my next toll road trip. As @dinkoh mentioned, they will do a plate lookup and charge the account for OC tollroads, but one freeway down here (the 110) makes use of the switched transponder to indicate a carpool. If we are carpooling (to the Rams game ) up the 110 and the transponder doesn't trigger, we will be charged via the plate lookup for what should be a free trip.

Not sure what the rules are in SoCA, but in NoCA I can leave our switchable transponders in #3, for all HOV lanes and paid time-of-use lanes. Since I do not need to fool with the switch, in my wife's S70D where there is no good position that registers in the front windshield, I have mounted the transponder in the bottom center of the rear liftgate window. Invisible as it is blocked by the middle seat headrest. Works great. And if you wonder why it is not mounted in the top edge, that is where the Blackvue rear camera is mounted.

 

[jf2go]

Not sure what the rules are in SoCA, but in NoCA I can leave our switchable transponders in #3, for all HOV lanes and paid time-of-use lanes. Since I do not need to fool with the switch, in my wife's S70D where there is no good position that registers in the front windshield, I have mounted the transponder in the bottom center of the rear liftgate window. Invisible as it is blocked by the middle seat headrest. Works great. And if you wonder why it is not mounted in the top edge, that is where the Blackvue rear camera is mounted.

I'm going to try upside down in the black area on my next trip (someone else mentioned that worked), otherwise I may try the rear hatch. I have tint on the back liftgate window, and concerned about attaching the velcro strips. I'm sure they would destroy my tint if I tried to remove them.

 

[jf2go]

Try it.... I did so at 65 and it blew out of my hand and into the northbound lane.
And that's why I now have the new switchie transponder.

Hmmm... hadn't thought of that. I will need to have a death grip on that thing if I try the sunroof trick.

 

[Moneesh]

Having started this thread a few weeks ago, then having tried all the various options, I have given up mounting the transponder on the windshield. I appreciate all of your suggestions to date. With all my attempts thus far and the transponder not working, they've looked up my plate and debited my account every time, with no violations. Yes, I do have the HOV stickers visible (as ugly as they are). I'm considering ditching the transponder completely as a result

I did read about someone putting the transponder (using velcro) on the bottom side of the back shelf in the trunk. It's not visible, but apparently gets read properly. That's going to be my last ditch attempt to use the transponder. Will let you know if it is worth trying.

 

[JPP]

I did read about someone putting the transponder (using velcro) on the bottom side of the back shelf in the trunk. It's not visible, but apparently gets read properly. That's going to be my last ditch attempt to use the transponder. Will let you know if it is worth trying.

I chose to not install the transponder under the parcel shelf as I do occasionally move/take out the parcel shelf and did not want to either forget it or have it tucked up away from the liftgate window.

 

[whttiger25]

Silly question - has anyone tried the frunk?

 

[JPP]

Silly question - has anyone tried the frunk?

Would not even bother - metal frunk hood would screen out RF.

 

[aaron0k]

It works mounted behind the nose cone on the classic MS; not sure if that is an option on the refreshed facade.