There should be a schematic posted on the inside of a panel somewhere. Post it; it'll say where each wire goes.
On the end of the red wire in the last photo it looks like a female & male mated connector
[the female connector is shown in the link]
with the mating connector broken off from its wire, so I'd look for a thick red wire that just ends. It probably broke off from fatigue, due to vibration in the unit. Wires in this kind of application need to be tied down.
Finding out why the breaker trips is another problem.
That one pair of wires in the lower center of the first photo looks like ordinary zipcord/lamp cord, maybe from someone who made a modification to this unit.
The wire end should probably be insulated - heat shrink tubing from your local h/w store would be good for this.
The lower left of the last photo also shows wire that looks like it doesn't belong. The insulation doesn't look weatherproof.
You have a DVM? A crimping tool or soldering iron?
In the lower center of the last photo on the control circuit board is an integrated circuit
Can you post the numbers on the top of it? I can't quite make them out.