Ran into an issue where my Dad's diesel wouldn't start one very cold morning. So I went to plug in the block heater and I noticed right away it wasn't going to work because the terminals on the truck side were terribly corroded. So after cleaning those off, I made this to cover the plug in hopes that it wouldn't corrode again any time soon. The strap is made from ninjaflex, so I could get it around the plug. The strap has a small loop and a big loop. The small loop goes onto the 3D printed cover. The big loop is for going around the plug end on the truck side.
You can use whatever settings you prefer. I printed mine in white abs @230c (heated enclosure) with 3 shells, and 4 top and bottom layers @60mm/s with great success. I didn't need to do any post clean up. I did turn the fans on at the beginning of the top of the knob to help the abs cure better. That helped keep the top knob more uniform.
For the strap I used ninjaflex @245c (heated enclosure) with 2 shells, and top and bottom layers @40mm/s. Turned out good, and wasn't impossible to get it around the plug.