Alluminum panel below sub floor

[JLGT5107]

Upon removal of forward sub floor I found this large section of alluminum. It was not fastened to skin in any way, but held in place with floor fasteners. there is corrosion at the bolts.Does any know its purpose? Attached to the underside is a 25 amp breaker in the wiring harness. Is this meant to act as a disaster fuse? It seems an odd location, as it is not accessible.

[wasagachris]

Judging from the location the aluminum plate you discovered looks like the upper cover for the spare tire carrier. If a spare carrier was installed the belly pan would be removed between the main frame rails from the first crossmember to the front C Channel. That area would then be exposed to the elements and this plate would protect the floor. Is that breaker installed in the wiring harness that goes to the tow vehicle? The breaker looks like one of those automatic resetting breakers. It would act like a surge protector between the tow vehicle and the trailer.