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HVAC Vacuum Leak?

97Ranger3.0

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South Carolina
Vehicle Year
1997
Make / Model
Ford
Engine Type
3.0 V6
Engine Size
3.0
Transmission
Manual
2WD / 4WD
4WD

So, I believe I have a vacuum leak somewhere in the HVAC system on my 97 Ranger. I don't know much about how the vacuum controlled HVAC works, so I don't even know where to start looking. I've attached a video to help show what is going on. I don't always remember this switch making so much noise, maybe it does and I just never noticed before. But when I switch to different vent settings, you can hear what sounds like air leaking out. It sounds like it's coming right from that switch. Again, maybe it's supposed to make an audible noise but I don't recall it always doing that. I checked the connector at the bottom of the backside of that switch that has all of the vacuum lines, and I don't see any damage and it was connected properly. I did a quick visual inspection of all of those lines as far as I can see, and I didn't see any damage to them. But again, all that noise sounds like it's coming right from that switch.

Also, the most noticeable issue I have is that when I use the A/C, the truck drives like it has a big vacuum leak. It rev hangs and the revs drop super slow between shifts, and when I push the clutch in to come to a stop, the revs jump or stay up to 1500-2000 rpm then slowly drop down. If this happens and I quickly switch it to the vent only setting, the idle drops back down quick like normal. This only happens on any setting that cycles the A/C compressor. If I just use the upper or lower vent settings, I don't notice any drivability issues. However, you might notice in that video that the idle actually jumps up just a tad when I switch it over to the lower vent only setting, but again I don't notice any change in drivability when on vent only settings.

I'm just looking for some advice on where to look and what to check, maybe even a vacuum diagram for the HVAC if someone has one. I'm just trying to avoid tearing the entire dash apart unless I have to. Thanks!
 


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97Ranger3.0

Active Member
Joined
Nov 22, 2017
Messages
164
Reaction score
60
Points
28
Location
South Carolina
Vehicle Year
1997
Make / Model
Ford
Engine Type
3.0 V6
Engine Size
3.0
Transmission
Manual
2WD / 4WD
4WD
Still looking for advice with this one...

The problem has gotten worse. Lately, my A/C will cut out if I'm going up a hill or accelerating hard (not full throttle though). Sometimes it will kick back on after a little while, but sometimes it just won't come back on for the rest of the drive after this happens. Also, it used to be immediate when I would switch to the A/C or Max A/C setting that the compressor would kick on. Lately it's been hesitating, often taking up to a minute or more before I here the compressor clutch kick on and for it to get cold after switching it to one of those settings. Also, when these things happen, the truck will rev up from an idle to 2k+ RPM and hold there, or if I'm driving it'll rev hang awfully between shifts. It seems like either a massive vacuum leak or that the ECU is expecting the compressor clutch to still be engaged and commanding the IACV open.

Any thoughts? Failing compressor clutch? Vacuum leak? Something else?
 

DeathRanger

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Kansas
Vehicle Year
2000 and 2019
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Ford
Engine Type
2.3 EcoBoost
Engine Size
2.3 L 4 cyl ecoboost
Transmission
Automatic
2WD / 4WD
4WD
My credo
This is my Ranger. There are many like it, but this one is mine.
I would guess vacuum leak from a bad hose. I used to have the same symptoms. I cant find exact pictures but it was a small grey hose on left side of engine that had melted and left dangling. 2nd picture is where it should be plugged in


61900


61901
 

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