Attention HomerWinzlow
Thread Starter
|
New User
Joined: Sep 2003
Posts: 2
Likes: 0
From: Birmingham
Attention HomerWinzlow
You seem to be the most knowledgeable on air conditioning problems. I would greatly appreciate your input on my problem. I have a 99 F150 with the 5.4. From reading other posts, I have what I believe to be a vaccuum leak. My a/c quits blowing and/or switches to defrost under hard acceleration and going uphill. Otherwise, it works fine and blows strong, cold air. I am as ignorant as can be when dealing with vaccuum lines. I know I am supposed to be looking somewhere behind the battery on the passenger side, but I have no idea what I am looking for. There are quite a few wires/hoses/lines running in all directions in this general area. Many of them are covered with some type of black plastic heat cover. Can you give me any advice on specifics of what to be looking for? Thanks very much in advance.
Logistics Pro
Joined: Jul 2003
Posts: 3,595
Likes: 52
From: Lawton, Oklahoma
Attention HomerWinzlow
Well unfortunately all you can do is trace back to the source, the reservoir, the in vehicle actuators, and the check valve. If you have a hand held vacuum pump you could check each device rather easily, but most home users do not have one just laying about. If the vehicle has been wrecked on the passenger side, one very highly likely cause is the vacuum tank cracked. Its located behind the battery and attached to the battery box. Just check each hose for cracked condition and the tank for any cracks, and check that the check valve in the line allows air to pass only one direction. There is a vacuum switch on the back of the mode selector switch at the control head, but I have seen very few of these go bad.
Thats really about all I can offer without actually being there to check it out personally. Best of luck and let us know how it goes.
Thats really about all I can offer without actually being there to check it out personally. Best of luck and let us know how it goes.
Thread Starter
|
New User
Joined: Sep 2003
Posts: 2
Likes: 0
From: Birmingham
Attention HomerWinzlow
Thank you very much for your quick response. The vehicle has never been wrecked, so I hope that rules out the vaccuum tank.
So, I should check the box behind the battery and all lines/hoses running out of this box? Are the vaccuum lines the very small lines that run out of this box? The lines I am referring to are larger than a wire, but smaller than a pencil in diameter. Is that what I should be checking? Thanks in advance.
So, I should check the box behind the battery and all lines/hoses running out of this box? Are the vaccuum lines the very small lines that run out of this box? The lines I am referring to are larger than a wire, but smaller than a pencil in diameter. Is that what I should be checking? Thanks in advance.
Logistics Pro
Joined: Jul 2003
Posts: 3,595
Likes: 52
From: Lawton, Oklahoma
Attention HomerWinzlow
OK, there are large vacuum lines going to the engine for vacuum source, a check valve, one small vacuum line to the vacuum tank, one small line to the firewall which goes in to the vacuum switch. Then there are all the various lines inside under the dash to the various actuators. Technically you should check them all from the engine, to the tank and on inside. Any one vacuum line disconnected or broken will cause your simptom. Any switch or actuator could have an internal leak. And the check valve could possibly not be holding when you accellerate allowing the vacuum to bleed off. You will just have to go one at a time by process of elimination.
