Offmetrolley battery lead

My trolly (pro rider look alike from ‘offmetrolley’) has had plenty of hard work for the last 4 years 2 to 3 times a week every week. She started playing up with the speed light becoming intermittent, I believe the battery charge status lights started to play up too, then she died. No display at all on the handle and won’t switch on. The battery is good, I can get the wheels to turn. There is no continuity between the battery connector positive to the red wire on the handle PCB but there is continuity from the negative to the black wire on the PCB. When disconnecting the main wire from the controller to the PCB I have continuity on red, black, yellow, and purple, but not on pink or green. Is this normal? Do these go elsewhere? Or should I start stripping out the main wire to look for a break?
Thanks in advance for your help.

The problem solved is to always check the basics first, which in this case I would go over and check the battery lead.  If it was only an intermittent speed light and not power shut down each time, I would suspect the controller. (Remember if the speed light has a consistent flashing, this normally means too low a charge in the battery.) Of course, can’t rule out any of the PCBs in the trolley like the handle circuit due to the fact the battery status lights were playing up. The controller is the main circuit within the golf trolley and can affect the trolley in many ways. So as for continuity, it’s very difficult to know if there is a break in the main wire without testing each wire from both sides. The controller to the handle circuit plays a role in feeding or not the power to the handle circuit forward and back.

Sorry, I can’t be more definitive with my answer, all I can point out is my best idea of what is most likely to be at fault.

Thanks, I changed the speed control switch and the battery lead, trolley working now.