Intermittent HVAV air flow problems
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Intermittent HVAV air flow problems
Hello to all. My name is Phil and I am new to the forum. I have an issue I need help with.
I have 2001 Ford Ranger XLT 5 speed with 2.5 engine. I has just started having intermittent air flow problem when directing air flow to the floor, dashboard or defrost. I have not disassembled the unit yet. It works sometimes, sometimes it doesn't. The heat/cool senor works fine. In researching the problem, I have come accross threads pointing to actuator motor, heat blend door and potential vaccuum problems. Do not believe it is the door, because of it were broke, it would not work at all. Actuator motor appears easy enough to get to but I have not seen an vaccuum lines. Has anyone had a simular experience? If so, I would appreciate your input with this problem. Can anyone point me to a diagram of any vaccuum lines that can cause this problem.
Thanks for your help
I have 2001 Ford Ranger XLT 5 speed with 2.5 engine. I has just started having intermittent air flow problem when directing air flow to the floor, dashboard or defrost. I have not disassembled the unit yet. It works sometimes, sometimes it doesn't. The heat/cool senor works fine. In researching the problem, I have come accross threads pointing to actuator motor, heat blend door and potential vaccuum problems. Do not believe it is the door, because of it were broke, it would not work at all. Actuator motor appears easy enough to get to but I have not seen an vaccuum lines. Has anyone had a simular experience? If so, I would appreciate your input with this problem. Can anyone point me to a diagram of any vaccuum lines that can cause this problem.
Thanks for your help
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Joined: Jan 2004
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From: SW Va
Welcome to FTE.
I agree, the blend door belongs on your suspect list, as well as a system vacuum leak. The blend door fitting may be cracked, not completely broken. You might check the hvac under hood vacuum source hose that feeds through the firewall, as it sees lots of under hood heat, so is prone to dryrot & leaking vacuum.
Check your under hood emissions decal for vacuum line routing. Also seeing as how you like to turn your own wrenches, check the "Tech Info" thread atop this forums thread listing page, lots of good repair info there, along with a blend door repair if you come to need it. Otherwise check out your local library, many have Mitchel On Demand, or other online auto repair links at no charge & you can print the info needed.
Some thoughts for consideration, let us know how it goes.
I agree, the blend door belongs on your suspect list, as well as a system vacuum leak. The blend door fitting may be cracked, not completely broken. You might check the hvac under hood vacuum source hose that feeds through the firewall, as it sees lots of under hood heat, so is prone to dryrot & leaking vacuum.
Check your under hood emissions decal for vacuum line routing. Also seeing as how you like to turn your own wrenches, check the "Tech Info" thread atop this forums thread listing page, lots of good repair info there, along with a blend door repair if you come to need it. Otherwise check out your local library, many have Mitchel On Demand, or other online auto repair links at no charge & you can print the info needed.
Some thoughts for consideration, let us know how it goes.
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An update for anyone that may have a similar problem in the future. I felt it was likely a vacuum issue. While trying to diagnose it under load, the problem went from intermittent to air blowing only through the defrost no matter the setting. This confirmed the vacuum leak.
So I pulled the line going from the vacuum canister to the firewall and was able to pull and maintain a vacuum confirming the problem was under the hood. Then pulled the line from the connector that leads to the canister on the supply side and could not pull a vacuum through the canister. At first I thought it was likely the canister, but after handling the line a few times realized that the black supply line to the canister had a hole in it. It had worn where it had been routed over the a/c line.
Neither of the nearby NAPA stores had the correct size vacuum line. So I simply cut out the bad section and spliced it together with a hose. Taped it up and put it in a conduit. I put it all back together, and it's working again.
Thanks for the help, pawpaw.
So I pulled the line going from the vacuum canister to the firewall and was able to pull and maintain a vacuum confirming the problem was under the hood. Then pulled the line from the connector that leads to the canister on the supply side and could not pull a vacuum through the canister. At first I thought it was likely the canister, but after handling the line a few times realized that the black supply line to the canister had a hole in it. It had worn where it had been routed over the a/c line.
Neither of the nearby NAPA stores had the correct size vacuum line. So I simply cut out the bad section and spliced it together with a hose. Taped it up and put it in a conduit. I put it all back together, and it's working again.
Thanks for the help, pawpaw.
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