UV and infrared blocking safety glass windshield

UV and infrared blocking safety glass windshield

Is there a solution regarding transponders and the windshield? It appears my Fast Track for toll roads (CA) and my transponder for community gates will not function when mounted on the inside of the windshield. They will only work if they are held outside of the car. Is anybody else having this problem?

Josh | 03. Januar 2013

There is a tiny spot on the right of the rear view (the checkered spot) that doesn't have the UV block. That is where I put my EZ-Pass and it works. Unfortunately you can't put anything else there... so if you have multiple things you'll have to put them outside. I am working on getting my local Tesla service center to install a radar / laser system outside the car as my V1 window-mounted unit is toast due to the glass.

Is a bummer the glass isn't an option... if was an option I would not have selected it given the issues.

But a small nit on what is a tremendous car...

mkh1437 | 03. Januar 2013

I have not tested it yet, but my understanding is that if you mount the transponder on the black-spotted area just right of the rearview mirror, it should work. That area is apparently not shielded.

DouglasR | 03. Januar 2013

Anybody know whether the Good-to-Go pass for Washington State can be mounted vertically rather than horizontally? That's the only way it will fit in the black spotted area to the right of the rear view mirror.

sbern18 | 03. Januar 2013

Ezpass in ny area works in spotted area only

DTsea | 03. Januar 2013

I would think, DouglasR, that the key is that the RFID chip be in the spotted area. The rest of is just a sticker I believe. sbern18, can you describe the installation? Those passes are really hard to get off if placed wrong and then you have to go buy another one...

Brian H | 03. Januar 2013

Is the UV block a coating? Can it be removed so the "hole" can be expanded?

DTsea | 03. Januar 2013

Hmm. Glass is relatively UV opaque anyway. I had thought the good to go passes were RFID (radio) not infrared... The WA DOT site says metallized windshields are the issue (especially with windshield heat which is a very thin metallic membrane). That would imply radio frequency. Good news is, for such cars (and apparently there are many) there is another option:

External Mount License Plate Pass

Mounts horizontally to the top of the front license plate using screws.
Chemical-resistant casing.
Best option for vehicles with windshields containing metal in the glass that may prevent a windshield-mounted pass from being read properly .
Available at Good To Go! customer service centers and online.
License plate pass installation instructions


That should work fine and $12 is not bad.

DTsea | 03. Januar 2013
DouglasR | 03. Januar 2013

@DTsea, I was going to try to avoid mounting a front license plate (until I get caught), so the External Mount Pass is not for me. ;)

However, I think you are right about these passes being RFID. I think I'll just try driving over the bridge while holding the pass up vertically in black checkered area to the right of the windshield mount. If the crossing gets recorded, I'll mount the Velcro there.

One mistake I made earlier while holding the pass up manually was that I had the Velcro facing backward (actually, my wife was holding it up). Of course, the Velcro should face forward.

TikiMan | 03. Januar 2013

I still haven't mounted my Fast-Trak (toll road) transponder yet, however, I will warn you that if you mount it on the windshield (up high) under the rear-view mirror, using standard velcro strips, and park outside in high-summer temps, the velcro glue will melt, and the transponder will dislodge (I know, because this happened on my last car, and it was sticky mess).

Has anyone tried placing it in the rear hatchback area (behind the rear passenger seats) under the rear glass?
I use to own a 1995 300ZX and it always worked perfectly (not sure if the rear glass in the MS is also coated with the same stuff as the windshield?)

DouglasR | 03. Januar 2013

@TikiMan, I long for weather that would melt my velcro glue!

Hodas | 04. Juli 2013

My Los Angeles FastTrak needs to be mounted somewhere convenient, because our transponders have a switch to set how many people are in the car, as HOV access/charges on the 110 and 10 freeways varies for time of day and number of passengers.

Fortunately, the spot next to the rearview mirror seems to be working ok for me.

I was faced with the problem of also having an RFID credit-card-style parking pass for work. I was going to just live with swapping it and the FastTrak as needed (fortunately my FastTrak use is mostly on the weekends), but I discovered that velcroing it to the small triangle of glass at the front part of the driver door works. You could not fit a FastTrak/EZpass there, but for card-style transponders this appears to be an option.

AmpedRealtor | 04. Juli 2013

Is there something special about Tesla glass?

Brian H | 04. Juli 2013

The windshield has a metallic heat barrier that also blocks RF. The dotted patch beside the rearview is supposedly "open", but some get better results attaching to the mount itself, or behind the plastic nose cone.

NICE | 04. Juli 2013

If your toll pass is thin enough you can slide it under the mirror mount. I was told there isn't any IR coating there. It works fine for me and has the added bonus of being hidden.

JPPTM | 04. Juli 2013

Some folks who do not need to fool with their transponder have mounted theirs behind the nosecone (search these forums and those on TMC).

Brian H | 04. Juli 2013

the inside (rearward) surface of the mount also works, it seems, because the mount is on bare glass.