Hey y'all, this is my first post. Just bought my first car, 1999 Jeep Cherokee 4 cylinder.

The A/C blows ice cold while the car is just idling or going under 20, but once I start to go over 20 or 30 the A/C starts blowing warm air. A/C also makes one click when I turn it on.

I have no clue what it is. Any ideas?

 

Congratulations on your purchase!

Does the air divert to other vents (floor, defrost) or does it just change temperature?

Start checking your vacuum lines... when the engine rpm is higher it is making less vacuum, so the system relies on the vacuum reservoir to move & hold the blend and divertor doors... but if there is a sizeable leak it causes problems.

On my pickup it won't lose the cold air, but it will divert to defrost when the AC is set to MAX and the engine rpm is up. Works fine in Normal, though, but that's a discussion for the Ford forum.

I'm not sure what the defaults are on the Jeep systems as I haven't yet had to get into mine, but they are vacuum controlled.

Good luck!

 

Yes make sure the vacuum canister is connected behind the front bumper on the upper side.

 

It doesn't divert air it just stops blowing cold. So I'll check the vacuum lines. Thanks

 

I will thanks