Normally, it was impossible to active the rear light despite the setting was correct. Recently I noticed someone suggest it is in fact possible. Follow the procedure below. 1: Go to rear cab and set the external switch on the control panal near dashboard 2: Set the light control (behind seat) to EMERGENCY by turing clockwise. 3: Check external camera--The tail light should be on and blinking 4: Set it back to Tail Light, now it should stay there without problem