We tow a 2014 Spark. The manual does not list any fuse to pull. We previously have towed for less than 4 hours at a shot and had no issues with the battery. I did turn off the radio. On this trip to snowbird in CA and AZ we towed for 9+ hours each day. I started the car the first day at around 3 hours in and again at the end of the day. The next day I went to start it after about 4 hours and the battery was dead enough not to start. At the end of the third day when we stopped for a week I had to jump the car off of the RV. This probably was not the best for the battery but I did not want to deal with it that second day at a rest area on the interstate where we stopped for the night.
My plan is to put a charge line in from the RV to keep the Sparks battery charged up. If I do not get that put in I might figure out what fuse to pull. But I think the charge line will be a better solution.
The reason to put the switch on ACC is to undo the steering wheel lock. On another forum someone stated that after 2016 there is no steering wheel lock. So if you are looking at that year it might not be needed.
Mike