This write-up covers one of those do-it-yourself projects that anyone can do and only costs a dollar. It won't make your TJ go faster, it won't make it articulate any better on the trail, and it won't get you un-stuck when you high center yourself on a big rock. What it will do is keep your passenger side carpet dry (and mildew free) and help prevent your floor boards from rusting (from the inside out).
If you've driven your TJ in an area where the summer temps and humidity ramp up to some short of nasty, then you may have noticed the passenger side floor area getting wet even though it's not raining outside. It comes from a poorly designed AC condensation drain that allows water to leak into the interior of your TJ.
The source of this problem is the design of the condensation drain that comes through the firewall on the passenger side of your TJ. The drain allows condensate water to drain out of the HVAC box and onto the ground. You may have seen your TJ dripping water near the passenger side front tire on a particularly humid day when you had the air conditioning running. The drain comes through the firewall and is surrounded by what looks to be a foam rubber gasket. This gasket doesn't do a great job of sealing the tube from the firewall and so the condensation flows out of the drain and then is blown back along the bottom of the drain, past the foam rubber gasket, and into the passenger area. From there, it flows down the floor board (beneath the carpeting) and accumulates in the lowest spot until you notice the carpet is wet.
The above photo was taken as I lay beneath my TJ looking up towards the bottom of the battery tray. The area circled in red is where the drain protrudes from the firewall (a little more than an inch).
The fix......$.99 worth of 5/8" (inside diameter) vinyl tubing purchase from my local ACE Hardware store. The 5/8" tube was a prefect "snug" fit on the drain tube. I slipped it over the drain and let the 12" long piece of tube hang down towards the ground. The condensation will now come out the drain and will continue flowing down the tube versus back past the foam seal and into the TJ's interior.
That's it folks. Nothing more to it. This topic comes up many time each month on the forums and after my TJ finally started leaking this summer, I decided it was time to take care of the problem. It took me longer to measure the drain diameter than it did anything else. Get your tubing and enjoy a drop free humid day!
Good trails and please TREADLightly!
4x4 Off-Road Homestead Firearms RC Flying