TJ air conditioning acting weird

[JamesAndTheSahara]

That's exactly what's going on. Your evaporator core (radiator looking thing inside your HVAC case) is freezing solid like an ice block. When that happens, no air can get through it (hence you hear the blower running but no air coming out). When you stop for lunch or leave it over night, the block of ice thaws and all that water drains out of your HVAC case drain tube (hence a big puddle under the Jeep). This problem is not specific to your TJ or Jeeps or any other cars out in the market. You typically see this problem happen when humidity is high and temperature is in the low to mid 70's. The humidity build up on evaporator core and can't drain out fast enough so it get's trapped between the evaporator fins which will eventually freeze and block the air flow. The culprit is the design of your HVAC case where your evaporator core is most likely sitting in the case at almost vertical position. It's hard for any condensation to drain out in that position. It's most likely designed that way because the'res only limited space under your dash panel and designing it say... 45° would require a lot of room. So there you have it.

BTW, this is one of the reason why your Jeep or other cars smells like something is dead inside when you first turn on the A/C. What you're smelling is mold build up on the evaporator core.

Same problem, not seeing a way around this lol. My AC works great until about an hour on the interstate and drastically stops blowing even on the highest setting. Any ideas on how to prevent it from freezing up?

 

[TJ4Jim]

I dirty evap will prevent condensate from draining off the coil properly causing the icing condition and considering the age of our Jeeps it will not be to uncommon. Newer vehicles employ a cabin filter which will keep the evap coil much cleaner over their life. A low charge condition will also cause the evap to freeze.

 

[Jerry Bransford]

Any ideas on how to prevent it from freezing up?

Move to Arizona.

 

[TJ4Jim]

Here are pics of dirty Jeep evap coils that can cause in icing, and unfortunately the only proper way to clean is by removing it.

 

[ultraboy]

Same problem, not seeing a way around this lol. My AC works great until about an hour on the interstate and drastically stops blowing even on the highest setting. Any ideas on how to prevent it from freezing up?

One way I was able to delay this from happening is running my a/c in recirc mode and max blower. But it was cold as heck inside the car. I guess you can point the vents away from you so you don't freeze.