If you are needing to correct the speedometer calibration on your 1992-1996 Ford F-Series Truck or Bronco, follow these easy steps.
Tools:
Wire With Alligator Clips On Ends
Checking the Conversion Constant:
- Press and hold the RESET button on the speedometer while turning the key to the RUN position.
- Release the RESET button. The pointer will move, and codes will appear on the odometer display. An "E" indicates English display mode (MPH), while a lowercase "o" indicates metric mode (KPH). Ensure the display mode matches the graphics.
- Press and release the RESET button again. The odometer display will show the conversion constant and "CAL."
- Verify the conversion constant displayed matches the correct value for your vehicle.
- Turn the key to the off position to exit the test.
Reprogramming the Conversion Constant:
- Locate the dealer mode programming connector below the center of the glove box. The dealer mode enable wire on all vehicles is Circuit #567 (LB/Y).
- Insert a metal clip into the service wire panel connector and connect the other end to the vehicle ground with the key OFF.
- Turn the key to the RUN position while holding down the trip odometer RESET button on the speedometer, then release the RESET button.
- The speedometer will move, and the display will show English/Metric modes and revision levels. The last number is the dealer mode programming lockout count.
- Press and release the RESET button to show the current conversion constant and "CAL."
- Press the odometer SELECT button to change the conversion constant to the correct value.
- Press and release the RESET button to lock in the new conversion constant.
- Turn the key off and remove the ground wire. Verify the speedometer operation.
Finding Conversion Constants for Tires:
- For 15-inch wheels, multiply the tire's revolutions per mile (at 45 MPH) by 0.0135. For 16-inch wheels, multiply by 0.015.
- Example: BFG AT 33x12.50R15LT/C with 636 revs/mile: 636 x 0.0135 = 8.59 (conversion constant).
Popular BFG All-Terrain Tires Conversion Constants:
- 30x9.50R15LT/C: 705 rev/mile, conversion constant = 9.52
- 31x10.50R15LT/C: 677 rev/mile, conversion constant = 9.14
- 32x11.50R15LT/C: 656 rev/mile, conversion constant = 8.86
- 33x12.50R15LT/C: 636 rev/mile, conversion constant = 8.59
- 35x12.50R15LT/C: 599 rev/mile, conversion constant = 8.09
