I have an after fit cruise control, a ZT11M which has 3 Buttons on the top Set/Acc, On/Off and Res/Dec then another 3 buttons which sets different speeds. I’ve no used it for a while and on a long trip today I couldn’t get it to work. The green light works to tell me that the system should be working. I then press one of the Speed buttons the light turns Red but when I take my foot of the peddle I loose power. Any suggestions?