Ok so my ac and heat are a little messed up. My problem is when I turn the air on, on any setting (vent, heat ect.) the air only come out the defroster vents. But when I change the temp from cold to hot the air switches and it only come out the foot vents. I have no idea what could be causing this

 

broken vacuum line to vacuum bal behind front bumper follow vacuum line from pass side fire wall by blower motor around battery to vacuum ball

 

thanks. fixed it.

 

kewl

 

So before I found this thread I did a silly thing and took apart the dial behind turning on the blower and choosing the direction. Now it won't turn on at all. Help!

 

i have the same problem with the air only blowing through the defroster. temp seems to work. followed the vacuum lines and found nothing wrong. any other ideas. also wondering what the operating temperature of the 4.0 l is. mine runs at 210 and gets a little higher after pulling off the highway and stopping for a while with the engine running. any help would be awesome

 

is there vacuum at the ball when motors running and 210 is normal ,as for the sitting search clutch fan trouble shooting for the sitting temp issue,also check if aux cooling fan is working

 

ill have to check that this weekend. thanks for the tips

 

I just put on a new aftermarket bumper and brushguard and didnt replace the ball because my engine ran fine. Then i wondered why my vents stopped working. Thanks so much, you saved me from tearing into my dash.

 

Thats completely normal, i put a 160 thermostat in mine and it runs about 170 when im moving, when sitting still it will still go up to 210 or so because the electric fan wont kick on until about 195-210 (stock thermostat is a 195) To compensate for that ive been considering buying a flex fan to replace my clutch fan. A flex fan has no clutch and therefore runs with the speed of the engine, and some are designed better than the stock, to move more air even at idle speed. Another option after changing the thermostat would be to get an aftermarket radiator that has better heat transfer. Griffin radiators makes models for cherokees that will cool much better than stock.

 

I live in central Arizona and have 2 Jeeps with factory 195 thermostats, functioning fan clutches, use AC frequently and mine run at 205* consistently whether idling, under a load on a hil etc. Point being, a cooling system in good shape will work fine without monkeying around with thermostats and the like.

So, Riff, a fan clutch replacement is likely in your future.

 

Same here, temps run well over 100 in the summer, 2 XJs with stock OEM cooling systems. Up hill, down hill, AC on never a problem

 

Thats TRUE, just suggesting options, of which arent all nessecary.I changed the thermostat in mine "just in case". I heard that the head is different on my 2001, than the pre-99 heads and that mine will crack easy if overheated. The 4.0 engine is great but they do tend to have overheating problems due to the small radiator. my buddys 90 cherokee has been overheating and is being remedied, i changed my thermostat as a prevention, while fixing my heatercore. I think if designed better, a vehicle wouldnt overheat quite so easy. However, If everything is working properly on a stock vehicle, there shouldnt be any problems.