I am having the exact same issue. I assume the relay was already replaced by cassmanbearcat because the relay is the little box next to the battery and if you short across it you can start the quad. Also if you pull the start cord manually with the switch on you can start it
now with that being said there is one other symptom.
When you turn the switch to the run position you hear the relay make a slight click / ding sound and about every 7 seconds the relay does a slight different sound and then 1/2 second later does it again. It also turns the light on and back off in the 1/2 second between clicks. This makes me think there is a short, but I don't see anything wrong. Also when I started having this issue it happened while camping, but messing with the switch got it to start so I thought replacing the switch would fix it. I think this is all the information that I can think of to offer and I would greatly appreciate some direction on this issue.
Thank you for any help you can offer.