Troubleshooting Transponder

Transponders registered in Washington are automatically forwarded to Idaho, South Dakota, New York, and Connecticut. For correctly registered transponders each state is responsible for their own bypass requirements.

Common Red Light Reasons

  • Overweight, over axle weight, or over-height
  • Carrier safety score of 75 or above
  • Expired commercial vehicle registration
  • The transponder is not registered correctly (still assigned to an old VIN)
  • Random pull in rate set by officers at the weigh station
  • Special emphasis, federal government inspections, or other mandated inspections


Preventing Red Lights

  • Center the commercial vehicle in the Weigh-In-Motion (WIM) lane
  • Maintain a steady highway speed of around 55 miles per hour
  • Provide at least a three second gap between vehicles
  • Secure tarps so the wind does not trip the over-height detector
  • Avoid dark metallic window tinting that can interrupt the transponder signal
  • Avoid metallic windshield visors that can interrupt the transponder signal
  • Use only one transponder in your commercial vehicle
  • CB’s may cause an interruption of the signal to the transponder


No Light

No lights in Washington are typically caused by a battery issue or the transponder location. Make sure the transponder is located:

  • Near the center of the windshield
  • On the passenger side of a divided windshield
  • Either three to six inches from the top or just above the dash board
  • Try to keep it a couple inches away from any metal

Battery Life

  • Transponders have a 3 to 5 year average battery life (depending on how often it is used).
  • Transponders are not designed with replaceable batteries
  • Once the transponder stops working, a new transponder should be purchased
  • The non-working transponder purchased from us do not need to be returned

Other Systems

If your transponder is working in Washington but receiving red light in other systems contact them at:

Contact Us

For faster service, please have your license plate and transponder number ready. The weigh station location, date, and time can also be helpful.

  • Phone: 888-877-8567
  • Fax: 360-705-6836