I've tried the search function here but can't locate anything My problem is that when I adjust my climate temp dial to cold (even with AC running) only blazing heat is coming through the vents. Outside temp was 45° F What should I check? I thought this was vacuum controlled but I have no idea where to start. It's a 2000 xj classic 4.0. Any help much appreciated!!

 

It runs by a cable. Your door inside the dash is stuck I bet

 

The HVAC system works off engine vacuum. Start by making sure that your vacuum reservoir is connected. It's the plastic ball mounted behind your front bumper, passenger side.

Follow the vacuum line into the engine bay and verify it's not cracked, disconnected, or leaking.

Post up your findings.

 

I located the reservoir and it is full intact... The lines are in good shape as well. When I went to check temp again... It's working fine now.... I'm baffled ???.... Engine speed didn't make a difference when I had the problem for a couple hours yesterday ... And it worked just fine at all RPMs now.... Hmmm I guess it could be worse... No heat in the winter?!!! Thanks guys for the input...