Connect to the main battery. The second battery now has a cover with a tamper proof seal as Ineos don’t want you to connect anything to that one. Connecting to the main battery is fine as you’ll be running the engine when using the compressor anyway as it has a large current draw.The key had not been in the ignition for hours. After driving for a bit, errors disappeared.
Did you connect the positive to the main battery or to the secondary battery if equipped with one? I’m currently connected to the main battery but, my brother said I should connect it to the secondary battery instead. Thoughts?