AC/heater issues
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AC/heater issues
I have a 1999. When truck is first started the fan works in all modes…defrost, A/C, heater both floor and dash. But after ten minutes or so the fan still sounds like it is blowing, but nothing comes out of any vent no matter what the setting. The lines under the hood are “frozen”.
Any help?
Any help?
Hotshot
Joined: Jul 2005
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the doors inside the duct that control air flow are vacuum operated. If you loose vacuum due to a leak, yo should get flow out the defrost toward the windshiled.. Leaks in the vacuum system are normally under the hoold at the fire wall, in front of the glove box area, or just toward the center of the motor. Vacuum hoses can crack and leak. There is also a vacuum canister inside the passenger front fender that can crack or hose fall off.... Last resort is hoses cam off on the dash controller or o-rings inside the controller have failed.
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see the hose schematic at the bottom of the post.
https://www.ford-trucks.com/forums/9...-please-2.html
https://www.ford-trucks.com/forums/9...-please-2.html
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DUDE!!!
so you already discovered the problem, you said "the a/c lines are frozen" what is probably the issue is your a/c compressor is not cycling! When that happens the evaporator becomes a block of ice... guess what air wont go thru ice!
Try this, either disconect the a/c clutch at the compressor, or disconnect the cycling switch at the accumulator (if you know what that is) or pull the compressor fuse then retest to see if it works better.
If this is the problem then the things that can cause that can be a bad cycling switch or a stuck a/c compressor relay. (Usually is the relay)
Good Luck
Try this, either disconect the a/c clutch at the compressor, or disconnect the cycling switch at the accumulator (if you know what that is) or pull the compressor fuse then retest to see if it works better.
If this is the problem then the things that can cause that can be a bad cycling switch or a stuck a/c compressor relay. (Usually is the relay)
Good Luck
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Thanks Dr. Rik
if am able to make progress by pulling the fuse or disconnecting the cycling swicth, can I travel any distance without causing further damage? I have no tools and I'm about 400 miles from them. I can make it without a/c or heat for that period personally, but I'm not sure what that would do to the truck
if am able to make progress by pulling the fuse or disconnecting the cycling swicth, can I travel any distance without causing further damage? I have no tools and I'm about 400 miles from them. I can make it without a/c or heat for that period personally, but I'm not sure what that would do to the truck
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From: St Louis
Disconnecting the compressor will have no detrimental effect on the truck. You'll just loose the A/C function and will still have normal heat, venting, and a non-dehumidifying defroster.
On a 99 F150, just pull the relay marked as either AC Clutch or WOT out of the under-hood relay box to disable the compressor. See owner's manual, if needed for relay identification.
On a 99 F150, just pull the relay marked as either AC Clutch or WOT out of the under-hood relay box to disable the compressor. See owner's manual, if needed for relay identification.
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one more thing
Like they sasy there will be no detriment to the vehicle by removing the fuse or the relay, however One more thing is once you remove the fuse is to make sure the compressor clutch no longer turns in the middle with the engine running. I have seen the gut package in the compressor colapse and keep the clutch engauged with out power needed to engauge the clutch. Thats all techno gook for just make sure the lines dont freeze up after you pull the fuse...
Good luck
Good luck
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