Defrost Only?

X

xyzzz

New Member
Joined
May 12, 2024
Messages
6
Location
Baltimore
Hi, all.

I had Two Issues with my 2002 TJ
Issue 1 - only pushing heat and A/C through defrost vents.
Issue 2 - HVAC Fan only running at Max fan setting

I went ahead and ordered a new HVAC Control panel and a new HVAC Resistor

I got the HVAC Resistor in, which fixed Issue 2

I got the Control Panel in, kind of. Panel went-in no issue, but the new Vacuum Line / Harness, which runs from the Control Panel to the Connector on the Engine Bay was way too short, so I could not replace the new Line / Harness. I noticed the original Line / Harness looked discolored. Should I get the more expensive Control Panel with the new Line / Harness, which is long enough? That runs about $220 or so (Standard Motor Products # HS-532).

I did inspect all vacuum lines in Engine Bay and all are in-tact.

So, I think, the Vacuum issue is actually in the Line / Harness off the Control Panel or one of my Vacuum Check Valves in the Engine Bay is bad.

Cruise Control works great, so I am thinking, the 'leak' is not in the engine bay. Or, am I wrong?

Should I do a smoke test?

Any other thoughts?

Thank you!
 
Last edited:
Could your blend door actuator be stuck, or faulty? I wonder if that and your resistor both had issues at the same time appearing as though it was a vacuum leak. Would be worth checking anyway as it's easily accessible under the dash.

I had a similar issue with air only blowing from defrost but also had no cruise control and realised a vac line was off on the engine. If you still have cruise, makes me think you don't have a vacuum issue. But I don't know enough about how the vac system works to be certain.
 
I will check, @AdelaideTJ!

One other important bit of information, when I disconnected the vacuum line / harness from the HVAC Control Panel, I did not hear vacuum escape, which is everything was good, I should have heard the pressure leaving?

Do vacuum check valves fail? I guess they could get clogged by something?
 
My issue was the off position on the far left knob did not work. I ordered the $60 ish unit from EBay. Like yours, line harness too short. Put new unit in and off now works but defrost only when on. Checked all my hoses, found nothing. Put old unit in and back to as before. Trying to return it now.
 
I will let someone more knowledgeable chime in on vac issues. I suppose the check valve could fail but I think you would've had other symptoms, such as losing cruise. I'm not really sure to be honest, but some of the very experienced folks on here should be able to help.

I think worth checking the blend door first and ruling that out as it is very easy to get to and a fairly cheap part to replace if it's bad. There are some suggestions in this thread that might be useful and lots of other threads here on the topic you can google. Hoping you just have a stuck one: https://wranglertjforum.com/threads/blend-door-issue-always-in-defrost-mode.56881/
 
Top Bottom
Back