[GoldiesPlating]

If you drive a Peterbilt 379 with a metal sun visor, your EZ Pass/Pre Pass may not always work. In fact, the manufacturer states it is not for use in trucks with metal sun visors. Don't believe them!
Here's the proper location to put it after much trial and error on my part. Install it with the 3 lights facing UP, 2 inches to the RIGHT (passenger side) of the center windshield divider, ALL the way towards the very BOTTOM of the windshield. This location conflicts with the printed instructions but does work best.
Mine now works everywhere and at every speed.

[mudawg]

If you have a sun roof that is the best place,the transponder readers are located overhead in the toll boths and the drop visors block the signal.

[GoldiesPlating]

True sunroofs are best but none on my truck unfortunately. (

[Jackrabbit379]

What about the chrome Texas drop-down sun visors? :P