If you have the Simpson Larwence sprint 600 as I did on my 2004 298SC there is no solenoid. it has a circuit breaker by your shins at the helm and runs off the windlass switch.
there is internal parts in the windlass that break and cause the problem, besides just being worn out and old. You can take it apart and fix it but it will break again soon and will be week. I did this and it ended up being a waste of time even though I did get it to work.
If you install a larger windlass you need a solenoid and bigger cable. the bigger cable may be installed in the anchor locker already but good luck finding the other end. ( could never locate it) A larger windlass will also require a heavier chain and rhode.
I installed a new Lewmar 700 windlass as a direct replacement and it works great and is stronger. Make VERY water tight wire connections in the anchor locker.