Stop in for a cup of coffee

The 50 get a regular not a slow blow. (ok no other way to say it)
Correct. I was saying a slower 40 might help if it wasn't already slo-blo. Since it is an actual higher draw while running hard. You want to give it a little extra (within what the circuit can handle) would be good to know more about wire size/circuit. Do you have a manual, or does it show if the 40 was actually correct. I never assume that the last guy put the right fuse in! If it ever had a direct short, the fuse size won't matter much. It would be a fraction of a second longer to take out a 50+ vs a 40