Hyundai Accent 2002 won't start

Hello Everyone,

I have a Hyundai Accent 2002 that won't start.

To put a bit of context, I left the car for 5 month at a friend place, who unfortunately never ran it. Everything worked good before, never had a problem starting the car. The battery is probably done, though we charge it back good and put jumping lead from another car, almost start this time but just almost....

I check a bit more in the car and found a cable that was unnatached. this cable came out from the dash as you can see on the picture, and end up close to the battery but I can not find where it should go. On the three cable, one is going close to the air exhaust, the other one close to the starter and this one that i don't know.







If anyone can help it would be really appreciated, as I am stuck far away on a dirt road.

Thanks all!