So it feels like the lock cable either broke (very unlikely) or came out of its mount. I may have not mounted it correctly when I was replacing the wiring harness.
Is there any way to get the seat off otherwise? I'm really stuck here and I really don't want to have to cut a gaping hole in the under tray to get my hand through.

TIA

 

This happened to me once and I was able to access the lock on a hot day. First I undid as many fittings to the rear cowl plastics and then as it was a very warm day I was able to bend the seat up so I could access with a screwdriver the lock catch - viola the seat could then be removed.

 

Thank you very much Wicky! It's only about 70°F here but I'm going to give that a try.

 

My hawk came with an old corbin seat that's pretty loose do it was actually pretty easy to remove the bolts holding the rear plastics on. Except for one which I ended breaking the mounting tab off. But it worked and I got the seat off. The locking mechanism is pretty loose as well so I had to zip tie the cable so it wouldn't come off the mount again.
I wish I could say that at least the engine is reliable but it eats a quart of oil and I still need to switch over to manual cct's.

 

This happened to me a few weeks ago....so I feel your pain.

Like Wicky said. .... you can pry the seat up enough to get at the 2 philips screws in the upper rear and the two cap bolts on the sides. Don't forget the two plastic push pin thingys underneath. I was able to get the cowl off enough to reach the latch cable but it was a total PITA.

The plastic end of the cable broke on mine and it popped out of position. I got a new cable and used zip ties and RTV so it will never come out again.

 

This happened to me. It seems the road crud that sprays up gummed it up and made it fail.

I used a long very flat flathead screwdriver from the side or back. The seat latch is only a C-shaped piece of steel in a standard spring catch. You can just push in a flat screwdriver to release it.

Look on here or in the manual to visualize the catch.

After that I bought a whole new cable and latch and religiously keep it clean and lubed to avoid the very feeling of grief you are feeling right now.