Tow Haul Indicator
WARNING: This page is about a different car, the 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The tow haul indicator illuminates when the tow haul button is pressed on the column-mounted transmission range selector lever. When the vehicle is in the tow mode, the indicator is illuminated by a signal from the PCM to inform the operator that the vehicle will not shift into overdrive. When the indicator is illuminated, the vehicle also provides engine braking and early transmission downshifts when braking on downhill grades.