Since we are being "honest"
Don't be too sure of what's "valuable" on eBay. it's always a gamble. When you think you've got something valuable for sale, chances are nobody wants it or thinks it's worth very much. I just got two fairly rare brake drums for $10.00 each. They are worth around $70.00 each - if you can fine them. I got a very rare "Volvo 122" script emblem for $5.00 and fine "B20" emblem for $5.00 Those items usually go for more than $20.00 each but since nobody else bid, I got them for far below the "Value"

So...
You could list it on eBay with a low starting bid (to lower your listing fees which are a percentage of the starting bid/buy-it-now) and hope that a couple people want it and it sells it for what NATAS thinks it's worth. Better yet, it might sit with one bid until the last three seconds of the auction when someone uses a sniping service to get you $1.00 more than the first bidder offered. You could try to guarantee that it sells high with a high starting bid, which could cost you higher listing fees and then if nobody bids on it and you are out some cash and still stuck with an AC. Even if it does sell, the buyer might come back and give you negative feedback because the innards are shot.

-or-

You could decide what you think it is worth to you and offer it for sale here on the brickboard and feel good that it is going to a good home and that you made an honest deal.

I'd personally recommend that you try and sell it to a volvophile locally.