what does a blinking level light mean

Purpose To indicate the position of the transmission control system "HOLD" switch. NOTE: The HOLD indicator also flashes to indicate the same pattern as the buzzer of the Self-Diagnosis Checker when the check connector (blue, 1-pin) is grounded. When the check connector is not grounded, the indicator flashes at a constant frequency indicating that trouble codes exist in the Transmission Control Module's memory. The diagnostic trouble codes will not display until the on-board diagnostic feature is activated.

A blinking level light suggests your vehicle is equipped with a rear Automatic Load Leveling package (ALL). When the ALL controller senses the rear air shock absorbers need to be raised or lowered to level the vehicle, the level light will blink while the adjustment is being made. The vehicle should be stopped or traveling on a relatively smooth road when this occurs. The light should turn off when the adjustment is complete. If the light stays on (not blinking), the ALL controller has determined there is a problem with the system. A dealer can retrieve trouble codes from the ALL system to help diagnose any problem.