Hiya Akiko.
I'm one of the few that actually watched season 7 and have the episodes on tape.
As I've said before, I only watched to see Fred in action as Rick Hunter. The show really wasn't all that good without Stepfanie, of course.

Some episodes had a decent run...
Anyway. Hunter and Molenski getting involved? NO WAY! Sorry to yell.

I don't ever recall anything near sexual tension at all between them. Joanne Molenski was nothing more than a partner, and in my opinion one on the tomboyish side too. Considering the type of women Hunter liked, she was sooo not the type. If anything, he might have thought of her as a kid sister or something, but it was never implied. Just my thought.
What site did you read about this sexual tension between them?
If there had been sexual tension with someone other than Dee Dee, it would have been Chris Novack (after Molenski) since they'd supposedly had feelings for each other at sometime.
Hope that clears up some of the mystery.