Novak Conversions Jeep Wrangler TJ engine mounts

A/C vacuum leak

Koda

New Member
Original poster
Joined
Sep 10, 2022
Messages
15
Location
Northern California
I've been trying to track down a vacuum leak that's impacting my AC coming out only the defrost vents. I bought a new Mopar line with check valves and swapped it out in the engine compartment. The T section that goes through the firewall is in good shape and not cracked.
I've inspected the colored hoses under the dash and swapped out the AC control unit, everything looks good.
The AC works fine until it's under load typically at higher speeds then it switches to the defrost vent.
Keeping it no higher than the 2nd position on the fan speed also seems to help.
If I shut it off after it switches to the defrost vent (still while driving) and wait 5-10 minutes and turn it back on it works again for a period of time.
I know I've got a leak somewhere, assuming under the dash, but not sure what to do next.

Any suggestions?
 
"swapped out the AC control unit"... looking at your picture I see you have a Jeep Rubicon (2003 to 2006). I have a 2006 Sport. Here is a shot in the dark... I had the same problem ( air coming out of defrost vent) when I replaced my entire A/C system for a beginning "black death" issue. Also had a vacuum leak somewhere that I could not find. Took out the control unit, took it apart and "did stuff" than cleaned. Put back in...same problem. Did it again... same problem with cold air coming from defrost vent only. Rechecked control unit and now noticed that it had been replace by someone who owned the Jeep before. Made in China. Turns out the 2005 to 2006 TJ's needed bigger barbs to connect the rubber hose manifold. The control unit I had the barbs were just a little bit smaller and would leak vacuum ever so slightly but still sort of worked. Used heat shrink tubing on the barbs to make them thick enough to fit the hose manifold. Success. I than bought this one.

55056558AA 55056558AB AC Heater Climate Air Conditioning Control Panel Switch Unit for 2005 2006 Jeep Wrangler TJ 05 06 2.4L 4.0L SM2141
 
"swapped out the AC control unit"... looking at your picture I see you have a Jeep Rubicon (2003 to 2006). I have a 2006 Sport. Here is a shot in the dark... I had the same problem ( air coming out of defrost vent) when I replaced my entire A/C system for a beginning "black death" issue. Also had a vacuum leak somewhere that I could not find. Took out the control unit, took it apart and "did stuff" than cleaned. Put back in...same problem. Did it again... same problem with cold air coming from defrost vent only. Rechecked control unit and now noticed that it had been replace by someone who owned the Jeep before. Made in China. Turns out the 2005 to 2006 TJ's needed bigger barbs to connect the rubber hose manifold. The control unit I had the barbs were just a little bit smaller and would leak vacuum ever so slightly but still sort of worked. Used heat shrink tubing on the barbs to make them thick enough to fit the hose manifold. Success. I than bought this one.

55056558AA 55056558AB AC Heater Climate Air Conditioning Control Panel Switch Unit for 2005 2006 Jeep Wrangler TJ 05 06 2.4L 4.0L SM2141

Thanks, I'll take a look at that.
 
Novak Conversions Jeep Wrangler TJ engine mounts