AC vent problem
Fleet Mechanic
Joined: Aug 2002
Posts: 1,568
Likes: 33
From: Swansea SC
Vacuum Hose
For the later model broncoes 92 on theres a white hose near your heater blower motor , seems this hose rots out faster than all ,get very brittle and if u do not touch it would be hard to miss seeing the cracks . Hope this helps Larry was that the hose (white) TR 
New User
Joined: May 2003
Posts: 5
Likes: 0
Ouch! Hose pinched and me, too.
I ran out of time before a desert trip and had to let a dealer have a go at it. Basically, I was right. The stiff, black tube that comes from the intake vacuum port and passes through the firewall at the passenger's knees was faulty. The (clueless) service manager said it was pinched. "How could it become pinched suddenly?" I asked. He answered, "Oh yeah, it was leaky, too." A couple hundred bucks for four feet of tubing!
OTOH, the dealer also found another problem that could have left me stranded in 105 degree wasteland, so it wasn't a total loss. Just a big expense.
I think this type of problem (faulty air flap operation)should be easy to troubleshoot, especially with a vacuum gauge. It would be very easy with a diagram of the system after it jumps off the diagram on the sticker that's near the radiator. The hassle is taking the dash apart and working in very awkward areas.
Still, the flaps will revert to Defrost any time the vacuum drops enough, whether in Vent, A/C, or Heat mode. The A/C compressor keeps running, but the cooling effect drops off (like when you're pulling up a long grade in the desert). That's just the way the system was designed.
OTOH, the dealer also found another problem that could have left me stranded in 105 degree wasteland, so it wasn't a total loss. Just a big expense.
I think this type of problem (faulty air flap operation)should be easy to troubleshoot, especially with a vacuum gauge. It would be very easy with a diagram of the system after it jumps off the diagram on the sticker that's near the radiator. The hassle is taking the dash apart and working in very awkward areas.
Still, the flaps will revert to Defrost any time the vacuum drops enough, whether in Vent, A/C, or Heat mode. The A/C compressor keeps running, but the cooling effect drops off (like when you're pulling up a long grade in the desert). That's just the way the system was designed.
Elder User
Joined: Dec 2002
Posts: 793
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From: SoFla
SoTumblemark- the black tubing from the vacuum intake was faulty and therefore the AC problem? Is the "faulty air flap operation" the same problem related to the black tubing?
So, your problem was resolve with replacment of the tubing, yes?
Dutch
So, your problem was resolve with replacment of the tubing, yes?
Dutch
Elder User
Joined: Sep 2003
Posts: 533
Likes: 0
From: Myrtle Point, Or
Originally Posted by Broncobirdy
Mine was doing the same thing. The vacuum line just inside the firewall near the heater hoses on the passenger side was rotted. I cut the hole short and replaced the boot from Pep boys I think. Works great now. I think my lines were white in color. Good luck.
thats what was wrong with mine too
I used a peice of vaccum hose to fix it, but now it atting to rott farther up the line, now I have to cut the cover to get to the hose.
Postmaster
Joined: Jun 2001
Posts: 2,809
Likes: 3
From: Loveland, CO.
Originally Posted by Tumblemark
Still, the flaps will revert to Defrost any time the vacuum drops enough, whether in Vent, A/C, or Heat mode. The A/C compressor keeps running, but the cooling effect drops off (like when you're pulling up a long grade in the desert). That's just the way the system was designed.
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