Your TJ has a couple mechanically/vacuum actuated flapper doors that block or duct the air to the floor, defroster, or dash vents. Someone is going to have to get in there and find out if a cable has come off or what's gone wrong. Now that we know the fan works and things are getting hot, it's impossible to say what exactly is wrong with those flapper doors... you're gonna have to get in there and have a look.
There is a couple of vacuum actuated flapper doors that might be causing the problem. Look up under the drivers side dash to the right and you should be able to see them. On mine the arm that attatches to the flapper broke off.
'97 TJ, 4.0L, AW-4, Flipped D300/4:1, ARB's, D44, Swayloc, RK LA, PC coils, Rancho 9000's, 33x12.5 Trxus, etc.
This is off topic, but I also own a little taildragger 2-seater Merlin GT bushplane. I had heard of this mountainstrip upp in the foothills of the Rockies northwest of Calgary. Last summer I drove my TJ upp there to have a look at what shape the strip was in and if I could land there. This year I flew up there just to find the strip full of cows, of all things. I guess I'll take the TJ the next time.
1997 TJ Red 2.5 L
BIG 50" wide 3X4 double square tube
front moose guard.