I never seen that before on a Carfax. Being below book value.

"- $90 BELOW book value." I know mine was $1100 OVER book value.

The seat heaters wouldn't be a big deal for me if they didn't work. $12.2k is a damn good price already IMO.
I only see 1 picture on the ad. Would be nice if there were more pictures. I say go check it out. Cash talks, I am sure you could get them lower then their asking price with cash.