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Discussion Starter #1
Hey all, I was driving the other day with the AC blowing full blast on recirc mode, and then suddenly heard a *flurp* and then only a little air would blow through the defrost vents.

After searching on here, I was lead to believe that there was probably (hopefully) a vacuum leak in the engine bay.

I checked the line that runs to the air intake, and it was in place.
I followed the line the other way to the cruise control cone thing, and the vacuum reservoir. Cruise control still works, but I checked the vacuum on the box anyway.

Vacuum check, no box: a little more than 15 psi
Vacuum check, with box: a little less than 15 psi
I assume 15 is good to go? I haven't found a value for that location...

Tracing that line back to the firewall, the only thing I can see that connects to the AC/blower system is a tiny fragile little hose: (post count too low to link to google drive :()

This seems fine? Am I missing something, or is there another hose somewhere?

I sat upside down in the passenger seat and adjusted the temperature knob.
I watched the blend door motor turn, so it's at least not the motor (maybe the doors?).

I see that the other recommended fix is typically the blower motor resistor.
The motor and AC still turns on, it just doesn't blow full blast, and only a little bit of air comes through the defrost vents (or a little cold air if the AC is engaged).

Do you still recommend replacing the blower motor resistor?

Is there anything else I can check in the engine bay, or get to easily on the passenger side without taking the dash apart and draining the AC system like WJJeeps/haynes manual instructs?

2002 WJ Laredo, standard temperature controls (not automagic)

Thanks,

JD

ETA: I R spell gud
 

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Discussion Starter #2
The issue ended up being the blend door mechanism failed inside the HVAC cowling.
Had to tear the dash apart to fix.

There are write-ups out there for "alternative fixes" that have you cut through the passenger side coming to get to the blend doors.

I'm not a fan of doing that, and felt like taking the dash apart allowed more room and overall ease of installation than doing something redneck and leaning in through the passenger floor.

It helps to have a helper. Those can usually be baited in with beer (at least mine can).
 

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Hey all, I was driving the other day with the AC blowing full blast on recirc mode, and then suddenly heard a flurp and then only a little air would blow through the defrost vents.

After searching on here, I was lead to believe that there was probably (hopefully) a vacuum leak in the engine bay.

I checked the line that runs to the air intake, and it was in place.
I followed the line the other way to the cruise control cone thing, and the vacuum reservoir. Cruise control still works, but I checked the vacuum on the box anyway.

Vacuum check, no box: a little more than 15 psi
Vacuum check, with box: a little less than 15 psi
I assume 15 is good to go? I haven't found a value for that location...

Tracing that line back to the firewall, the only thing I can see that connects to the AC/blower system is a tiny fragile little hose: (post count too low to link to google drive :()

This seems fine? Am I missing something, or is there another hose somewhere?

I sat upside down in the passenger seat and adjusted the temperature knob.
I watched the blend door motor turn, so it's at least not the motor (maybe the doors?).

I see that the other recommended fix is typically the blower motor resistor.
The motor and AC still turns on, it just doesn't blow full blast, and only a little bit of air comes through the defrost vents (or a little cold air if the AC is engaged).

Do you still recommend replacing the blower motor resistor?

Is there anything else I can check in the engine bay, or get to easily on the passenger side without taking the dash apart and draining the AC system like WJJeeps/haynes manual instructs?

2002 WJ Laredo, standard temperature controls (not automagic)

Thanks,

JD

ETA: I R spell gud
Right behind the right headlight assembly is a vacuum reservoir. It's used to ramp up/save vacuum to vacuum operated systems (blend door system, cruise control) It has a 1/4" vacuum line from it to a vacuum tee about 4" away.
My air only came out the defroster too. I found the small vacuum line broken right at the tee in the engine bay. Fixed it, and no change.
When I pulled the headlight assy out, the 1/4" line was crumbling away. Replaced it, and lo and behold, the blend door worked! Hell, all the vacuum operated systems, even the brakes, work better.
Just be careful when you get behind the headlight. There is an impact sensor right below it. Make sure to pull of the negative battery cable and wait a couple minutes to make sure the airbag system doesn't get activated.
 
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