Low voltage
It is a must to carry extra fuses of several sizes that are for the HiLo. Cheap insurance. One time we just had our home furnice tuned up. Later that night it quit working. The tech came out the next day at 8AM. Turns out a fuse was in the furnice and it had blown. He was going to take out a fuse from his truck dash. DH to the rescue with his ample supply of truck fuses. Good many years later. We also have extra hitch pins in the glove compartment. A friend of ours noticed his towed car was going sideways because he had lost the hitch pin. His wife had to drive the car. Always good to carry spares.