Transponder Mounting Instructions

As indicated in your I-PASS Owner's Manual, your transponder must be mounted inside the vehicle on the windshield approximately 1 inch to the right/left of your rearview mirror post and 1 inch below metal roofline to ensure successful toll payment.

I-PASS electronically collects tolls using a radio frequency system which “activates” your transponder about 300 feet before the deduction is taken. Therefore, you cannot wait until the last minute to take the transponder out of your glove compartment or wave it as you approach the toll plaza since such actions interfere with the activation of the transponder. For the less than 1 percent of cars where I-PASS does not work due to magnetic windshields, alternative mounting instructions are available or a bumper-mounted License Plate Tags (LPT) that operates the same way as a Flat Pack Transponder can be purchased.

Download I-PASS Mounting Instructions (pdf)
Review Sample List of Vehicles Requiring a License Plate Tag (pdf)

1. Ensure the inside of your windshield is clean, dry, and warm.
2. With the arrows of the transponder pointing toward the roof, align the transponder on the windshield behind the rearview mirror at least one inch below the metal roofline and one inch to the right or left of the mirror post.
3. Remove the plastic backing tape from the removable DuaLock strips and firmly press the transponder against the glass for 15 seconds.

For vehicles with vertical windshields, such as Jeeps, buses, or trucks, I-PASS transponders must be mounted in the center of the windshield, about one to two inches from the bottom of the window. Otherwise, it may be difficult for the Tollway’s I-PASS equipment to “read” the transponder’s signal.

If you determine that your windshield contains metal components, please request our I-PASS License Plate Tag (LPT).

Instructions for mounting a License Plate Tag (LPT):

1. Identify the back of the LPT by finding the arrows next to the mounting holes.
2. The LPT must be fastened to the front license plate using the plate's top mounting screws.
3. Use your license plate screws and the knock-out holes in the LPT case to fasten it to your front license plate.

Instructions for Exterior Mounting

E-ZPass Compatible Transponder

1. Adjust the driver’s seat and rearview mirror to your normal driving position.
2. Make sure the windshield is clean, dry and warm.
3. The recommended position for LCD transponders is to the left of the rearview mirror post.
4. Adjust the location of your transponder to meet the following conditions before mounting it on your windshield:
   • The top of the transponder must be a minimum if 1 inch from the roofline.
   • The edge of the transponder must be a minimum of 1 inch from the rearview mirror post.
   • The LCD display panel should be visible in normal driving conditions.
   • The transponder does not obstruct road vision.
5. Remove the plastic backing tape on the enclosed Dualock strips and firmly press the transponder against the glass for 15 seconds.

Refer to the sample list of vehicles with special features identified by the Illinois Tollway as having special features that require alternative mounting placement or an exterior License Plate Tag (LPT). In general, windshields that contain metal in the glass (metal oxide) and mirrors with compass or temperature readings may prevent the I-PASS signal from being read properly. Also, windshields with the following glass features may interfere with the I-PASS signal and require alternative or exterior mounting: solar ray, solar tint, heated, heat reflected, insulated, Insta-Clear. If you are unsure if your vehicle has one of listed features, contact your dealer.

Test your I-PASS to make sure it works by driving through a tollbooth lanes at a mainline plaza or refer to the customer service chart for a testing location.