It is probably under the forward berth at the very forward end (on the fwd bulkhead which forms the aft wall of the chain locker).
At least that is where mine is.
PS - I am thinking of relocating mine to be higher up the same bulkhead, but above the berth (just under the deckhead). I like this for easier access and a drier location. Also, the hole through the bulkhead for the cables from the solenoid to the winch would then be well above the chain pile. At present, the hole is buried under the chain and the cabling is exposed to the chain.