Hello, first post ever:
This just happen to me. The cable actually came disconnected from the seat catch link. I removed the left side cover and disconnected and pulled back the center cover. After reviewing the parts assembly (
http://www.cheapcycleparts.com/oemparts/a/hon/506cb70ef870023420a41a4f/seat) got a coat hanger and bent the end a little more than 90 degrees approx 1/2 inch on one end. From the center between the upper top frame you can slip your hand in and just fell the catch link with you finger (I have average size hands) I took the coat hanger and was able to guide it in with my finger and insert it in the catch link (where the cable is supposed to connect) and then pulled forward on it and it unlocked. It might be helpfull if someone is pushing down on the seat when pulling to take the pressure off the catch. No matter what the cause of failure, the only way to release the seat from the catch is to pull the catch link forward. Hope this helps.