My trolley has developed an intermittent fault. Sometimes it works fine and then it will only go on very fast speed when the control knob is switched on and turned even if the knob is turned very slowly. Switched on and off again it sometimes works perfectly .
Do you think I need a new switch or a new speed controller.?
The best thing to do is test it a few times and if the speed control knob seems to be erratic, then it would suggest a new speed knob is needed. Speed control switches are the most common fault as they can get damaged easily by way of a knock here or there. The continual movement can also wear them out. If as you say the control knob even if rotated slowly, jumps to full speed after a good turn, this could indicate the speed knob not delivering any current until it hits the contact at speed 7. It is difficult to say from a distance but if the speed jumps as soon as you switch it on just as you turn the dial and wont turn down again, it could be the golf trolley controller at fault, especially if it works sometimes and happens occasionally. The other symptoms of a controller fault is as soon as the trolley is switched on it goes full all the time without any way of controlling it.