I have a TJ wagon. A coule of days after we've had some rain, there's a real horrid wet carpet smell in the car. I've been trying for ages to find where it's coming from but had no luck.
A couple of days ago my wife took it through an automatic carwash and my daughter screamed because there was water running down the rear driver's side seatbelt and going all over her. Where could the water be coming from? The rubber around the door looks ok. Could it be coming in near where the rear window meets the door?

Ive heard the rear side windows in the wagon can have the seal go? Have a look around there or get someone to sit inside and start gently with a hose and work your way from the bottom up looking for where the hose is when water starts coming in. If you can work out the right keywords to get the the search function on this site working there might be a thread with the fix posted in it in more detail.

Yeah sounds like the seals in the rear windows. Very common. Take it to a windscreen place and they will do it for you. Shouldn't cost too much. They need to totally remove the old glue/sealant before applying new stuff.

This might sound silly but take it through another carwash, pinpoint it, then take it to a window place.

Rather than go through and automatic one you should just be able to have a friend spray it with a high pressure hose in a self serve one. So you can stop spraying once you find it rather than put another bucket of water in it.