Dick is correct (may also be used for lighting) If you crawl down in the
aft locker on the port side you can easily find the other short ends.
Catalina was extremely thoughtful in that it can be almost impossible to
run these wires without removing the stern rail assembly. Navpod used to
sell a high end pod /speaker combo that mounted under the seats. I've got
an LED flood light that I'm planning to mount for nighttime dinghy