Here’s a fuse guide.
I know, this is Car Talk, but couldn’t you throw in a penny for the 15 amp AC household circuit in your Grandpa’s house?
Years ago I had a friend who had a Honda Accord. One weekend she offered to let me ride w/her to a group camping trip hundreds of miles away. About every 50 miles the car would stall out for no apparent reason, she’d coast over on the freeway shoulder, and insert a new fuse somewhere. She didn’t even leave the driver’s seat, just remove the old one, get the fuse from the glove box and put it in. She could do it all without looking, just by feel. 50 miles later, same thing. 50 miles later, same thing again. I decided to ask her about this unusual behavior; she replied it was “just an Accord thing” . Her method seemed to work ok, we arrived on time. And made it back using the same method. She kept a box full of the needed fuses in the glove compartment … lol .