No air in Jeep.

[Paul Bruchal]

Bought this Jeep over the summer and all the air controls worked. Had a vacuum leak so it defaulted to defrost only and I fixed that. Soon as I fixed that vacuum leak, my air only worked randomly, like, when ever it wanted to blow air, not on demand. And now it never works. Fuse isnt blown. 25A.

I'm wanting to delete my AC and only have heat for defrost. But since its getting colder out, my windshield at night gets ALOT of condensation on it and needs the defroster.. and i don't even have that.

 

I need some help please!~

[SBpunk]

Does the compressor kick on? If so, how often? You might have a leak in the AC lines or low on coolant (usually the leak causes the low coolant). Take that to get some dye put in and see if you can trace down the leak. If that doesn't work I'd start looking into the other components like blower motors, vent doors, etc. The heat/cooling systems in jeeps are garbage and they didn't get any better over the years.

[gogmorgo]

The MJ's hvac was originally designed for a cabin with around three times the volume, so it's way more effective than it needs to be. I almost never have mine all the way hot, even at -40.

If I understand it right, the op's blower motor is intermittent. If that's the case, check for power at the motor, and if there's consistent power and no fan, replace the motor. If you don't have power there, the next thing to check for is a bad resistor pack. Typically when a resistor pack goes bad, it results in max fan speed or nothing, but I had two in the same week in two different vehicles at work this summer go bad and completely kill the fan.

 

If however what's happening is that you have no heat but every other aspect works, I'd look into making sure the engine's cooling system is in good shape. Start by making sure the coolant is clean, with a good antifreeze ratio, and the system is full. If you have to replace your coolant, do the following while it's drained so you don't have to dump out the new stuff: Make sure your thermostat is working properly, and then your heater control valve (protip: your heater valve causes more problems than it solves, so look into just getting rid of it.) and flush your cooling system, the heater core in particular. If you didn't have to replace your coolant, you may still have to do that stuff anyhow, so be prepared to dump and replace at least some coolant.

[Paul Bruchal]

AC isnt the problem because I have half of it un-installed already. "taking it out"

I know I don't have heat because I need to flush the heater core out.

I need to find some leads to my DMM and check for power at the motor and check the resistor/find it.

 

Tonight I tried the defroster again. It did turn after running the Jeep for 15 min, it blew warm, then cold air.