transponder mounting

transponder mounting

What is the best location to mount a transponder (like EZ Pass) on the windshield?

kagai | 22. november 2016

None? I have a gate pass that I've never been able to use from any location on my windshield, or even waving it through my driver's side window. I always end up having to either open my window, or wave it through the pano roof

lilbean | 22. november 2016

The transponder folks told me the best place is to the right of the rear view mirror.

MilesMD88 | 22. november 2016

right of rear view mirror +1

Suraj | 22. november 2016

there is a 2 X4 inch oval black spot immediately to the right of the rear view mirror. Is it Ok to mount it over this spot?

lilbean | 22. november 2016

I don't see that spot you are speaking of.

Suraj | 22. november 2016

immediately to the right of the mirror mount on the windshield, there is a darkened area, slightly larger on the right side. Wonder if that should not be covered up!

rxlawdude | 22. november 2016

There are so many windshield variants over the years. Current production cars have an area immediately to the right of the rear-view mirror/autopilot camera housing, as high as possible on the glass.
Note also that the orientation of your EasyPass may be critical, as the antenna in the transponder may be located in a relatively small portion of the case.

lilbean | 22. november 2016

Thanks for the info, @rxlawdude!

kagai | 22. november 2016

@rxlawdude - I really can not use my RFID gate pass from anywhere on the windshield, or even waving through my driver window (it works just fine if I happen to use a different vehicle). The gate readers are on top and on the driver side as well - plenty of opportunity for it to be picked up - but for some reason, in the MS, I just have to open the window. What gives?

Haggy | 22. november 2016

"Using RFID Transponders

Model S has a metallic coating on the
windshield that can interfere with signals sent
from RFID transponders used by many toll
systems. Most Model S vehicles, depending on
date of manufacture, include an area in the
windshield in which the metallic coating is cut
out to accommodate transponders. This area,
located on the right side of the rear view
mirror, is the best location to mount an
transponder. If your vehicle does not include
this cut out area, mount the transponder to
the rear window.

Note: You can also attach a weather-proof
transponder on the front license plate or
behind the nose cone (for details on how to
remove the nose cone, see Instructions for
Transporters on page 172)."

rxlawdude | 22. november 2016

@kagai, I'm guessing your gate pass uses far less RF energy than the toll transponders that must work with vehicles at speed. You can try attaching the gate pass to the back hatch, or (less preferential) inside the nose cone.

kagai | 22. november 2016

I have an MS Refresh (no Nose cone) and my gate pass is not weather-proof. I've literally tried every placement on my windshield to no avail. Stopped at the gate a few times, and even moved the pass all over my windshield - no luck.

Even the reader that is closer to the driver's window only reads the pass when the window is down.

My gf's car works just fine with this same reader, on either the window or pretty much anywhere on the windshield.

I've resolved not to stick it anywhere and just open the window and wave it, but it's really annoying.

p.c.mcavoy | 22. november 2016

I have a refresh MS 90D. I have my EZPass mounted in the blacked out area just to the right of the rear view mirror. Mine is one of the smaller, rectangular versions. Have it mounted sideways, long axis vertical. I don't use it a lot, but did in Chicago area about a month ago. Did have issue with one old style gated booth coming south out of downtown on I-90, but car in front of me did as well (not a Tesla), so figured that was just and issue with that booth. All others, including one other old gated style as well as all the high speed tolling spots worked fine. I did have my license plate entered against my tag, so impossible to tell if the high speed tolling ones were based off of visual recognition of my plate or from reading the transponder.

Here's link to a photo I've posted if that helps you any. (I still haven't mastered posting photos yet on this forum!).

mm7nyy | 22. november 2016

I have a exterior transponder attached above my front plate as recommended by my service center

lilbean | 22. november 2016

Does it work in the frunk?

murphyS90D | 22. november 2016

No, the hood is aluminum. Radio waves don't go through metal.

lilbean | 22. november 2016

Ok. Good to know thank you.

lilbean | 22. november 2016

This is what I do with my transponder. I just throw it up between the sunshade and the glass and it just rolls around all willy nilly and it works every time. I don't like to stick the adhesive on the glass.

mrjjp | 22. november 2016

I have my transponder right next to the rear view mirror base housing. I does touch the base. Just tried it there because everyone in this area has a front mount ie over the license plate. This location is good enough for me.

Rajayla-1 what model did you get??????

High Plains Drifter | 23. november 2016

External license plate mount.

nipper2 | 23. november 2016

@mm7nyy Did you have to remove the license plat trim in order to get the transponder on? Or did you get longer screws?

StarKiller | 23. november 2016

@Rajayala1 | November 22, 2016

"immediately to the right of the mirror mount on the windshield, there is a darkened area, slightly larger on the right side. Wonder if that should not be covered up!"

I know what you are referring to. I have mine just slightly to the right of that darkened area.

EVRider | 23. november 2016

As others have said, if your windshield has the dark patch to the right of the rear view mirror, your transponder will work there. I've successfully used both a FL SunPass and MA EZ Pass (formerly FastLane) transponder in that spot. Note that my SunPass transponder is actually larger than the patch, but it still works there.

This has been discussed in many other threads too; see this thread for help on searching the forum:

mm7nyy | 23. november 2016

@nipper2 I live in NY and the screws were supplied by ez pass, previous screws were replaced with one-wayscrews my service center installed without a problem

nipper2 | 23. november 2016

@mm7nyy mine came directly from EZ pass but no screws. where they able to leave the chrome frame on? I will need to find some one way screws.

mrjjp | 23. november 2016

Wonder if the screws were gold ?
They are the only ones that will attach to glass!
mm7 and nipper2 eat lots of turkey.

nipper2 | 23. november 2016

@mrjjp Pasta

Dofpic | 23. november 2016

Here is the best place. Mount it in the REAR windshield place it where you do not see it in the rear view mirror up at the most forward spot of the windshield , then mount it back an inch or two.. Always works. The only thing is sometimes you have to pull farther up into the booth for it to trigger the gate but it always works. The local service center told me this.

sward2 | 29. august 2019

I just installed my Florida Sunpass in the darkened area to the right of the rearview mirror. I mounted it vertically and I hope it works. I have yet to field test. Who knew that this would be an issue?
I have a S 70 CPO with 17 K on the odo. | 30. august 2019

Why is it an issue if you haven’t tested it yet?

EVRider | 30. august 2019

@sward2: That’s where I mounted my Sunpass in both my old and new Model S and it worked. Not sure what you mean by mounting vertically, but mine is mounted using the normal orientation.

spineeric | 02. september 2019

I occasionally use the HOV lanes in California so I do not leave the transponder stuck to my windshield. When I need it I mount it just to the right of the rear view mirror at the top edge of the windshield. Works every time. Below is the link to the holder that I use. Tesla Service Center saw this in my car and told other customers about it. The price has increased since I bought it!

Renzo | 05. september 2019

I have a 2013 model S and I was not able to install the sunpass on the dark area of the windshield by the rear view mirror because that area was not flush so the suction cups would not stick. I ended up buying an external transponder and my service center installed it for free the next time I was in there for warranty related issues. they ZIP tie it to the front metal bumper bar behind the nosecone.

EVRider | 06. september 2019

@Renzo: The nosecone option went away when they redesigned the front end in 2016, but the suction cups do work in those cars, so they must have changed the windshield, maybe when they added AP1 hardware in 2014.