Denny, I have a 1980 23 a very similar boat to your 25. I have a female recpticle imbeaded in the top of my cabin. I was able to find a direct replacement from West Marine. The biggest problem I had was insuficent wire length to connect the new fitting. It was a struggle but I was able to get it installed.
It sounds like you do not have this fitting. I learned this past winter when I had my port bulkhead out for repairs that for about 4" the wire was exposed in the trough moulded into the cabin top that the bulkhead slides into. The wire than disapears into the cabin top.
To remove the port bulkhead, you will need to remove the compression post first, than slightly jack the cabin ceiling up about 1/4" than the bulkhead will slide our after all the fasteners are removed.
Keep in mind my boat is a 23, double check with a fellow 25 owner. Good Luck