I just used one of them to power a linear actuator to move the discharge chute head on my front mounted snow blower. It is fed through the cigarette lighter on my L3430 (factory cab version)
Looked small to me too, and I wanted to run 4 lights, so I just ran a new fused wire from the hot side (battery connection side) of the starter to the back where I mounted new switches. Philip.
I have no experience with the Grand L, but on the plain L series there are bullet type connectors under the fenders for work lights. As I recall the work light circuit has a yellow-with-black-flecks or black-with-yellow-flecks wire and runs to a 10 amp fuse in the fuseblock.
They are for the work lights. Just remember that it's a 10 amp circuit so the wires don't need to be too large. But it also limits the number of lights you can have on at the same time.
If you are concerned the wires are not large enough to power the lights safely then have them be the hot wire to power a relay and pull your main load on a larger gauge wire.