Obscure 40A interior fuse

[Granite Goat]

I blew the F7 interior fuse on my 2026 1500 Bighorn. It is a 40 amp (FMS-40) that provides power to the trailer brakes and controller.

I hit two auto parts stores as well as my local dealership this morning and nobody carries it. I find it super frustrating that the dealership doesn't carry what should be a common consumable for something they sell. FWIW, the Mopar p/n is 68377879AA.

 

[Granite Goat]

I should have test-driven a new truck amd helped myself to what I needed

 

[UnloosedChewtoy]

A lot of newer vehicles are using more and more of those style fuses. I've seen them called case fuses, casement fuses, and cartridge fuses, but I believe this specific fuse is called a MCASE+. And yes, you are right, a lot of local auto parts stores' selections of them are quite limited.

Some general casement fuses (which the MCASE+ is a subcategory of) can swap in its place, some cannot, reportedly. I've never had the misfortune of blowing one to have to test that theory, but I do have a small multipack of casement fuses in the passenger side Rambox just in case.