2. If the fluctuation of the landing bar is large, it is necessary to check the length (weight) and spring tension of the brake bar, adjust the position of the stroke control, and tighten the connecting bolt of the tension spring.
3. If the parking lot switch fails, first test whether the red (yellow) and white wires of the motor are connected, and then test whether the blue-gray (green) signal wire is short-circuited with the K2(K 1) sensor switch.
4. If the chassis has abnormal noise, it is necessary to add lubricating oil to the bearing and movable connecting rod or replace the bearing.