FS GT3C with throttle trim and end point adjustments issues

You can see that when I trim the throttle forwards nothing happens but when I trim backwards, the wheels start to move forward at the end of the trim limit. End points affected as well. It is clear that the indicating arrow stays on "back" setting unless I have the trigger squeezed. As soon as I release trigger to neutral, the "arrow" returns to back setting. I haven't noticed any other issue. Trim and end point seems to be working ok for steering and 3rd channel. I tried reset by removing the battery and cleared all stored settings and vehicles but this didn't help. It gives me exactly the same issues even with the receiver and ESC off. Other than this, the radio drives the car ok. System consists of an FS-GR3E receiver, Tamiya TBLE-02S controller, Tamiya 540 torque tuned motor and 7.4V 3300mah lipo battery.