Heater control

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May 21, 2006 | 04:17 AM

Fordteamone

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From: Concrete WA

Heater control

I am not having luck with the search. Can someone please point me to a post on how to troubleshoot the heater controls for a 2000 F150 XLT.? We have checked the **** and it looks good. It acts like the blend door is not switching. AC coming out the defroster. Thanks for you help.

May 21, 2006 | 07:58 AM

steve(ill)

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the blend door controls the temp. there are a couple small vacuum cylinders that are ON or OFF. they direct the air to the defroster or the floor. when the air is directed to the floor, there is a second door that can send air to the dash panel. if the first cylinder fails or sticks, the air always goes to the defroser.---- under the hood, behind the battery, there is a small vacuum tube that has a TEE and goes thru the firewall toward the glove box. look in this area and see if the hose is cracked or TEE broken. pull the hose off when truck running and see if you have good vacuum from the motor. suck on the hose and see if you can open the vacuum cylinder in the cab. lay upside donw on the drivers floor and look up above the gas pedal toward the radio. i think you can see one of the cylinders, i dont remember which one.---- there is more in the search somewhere.---- you are probalby looking for a vacuum leak at the fire wall, best guess.

May 21, 2006 | 09:29 PM

Fordteamone

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From: Concrete WA

Steve
Thanks for the help. I found one post about repairing the blend door motor using the search for 1997 to 2003 and it just did not seem to match the truck. That led to the question above. I will follow your advice. AC and Heat seem to work but defroster is the only outlet. Thanks FTE.

May 21, 2006 | 09:37 PM

CaptKim

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Heater Control

Don't know if it will be much help but I had a vacume leak in one of my lines and a broken line that caused my louvers not to work

May 29, 2006 | 07:42 PM

Fordteamone

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From: Concrete WA

Steve

Great instructions thanks. Behind the battery we found a vacuum line chewed in half coming off the front side of the tee on the firewall and about 6 inches long. Can not find the other end? Where is this line supposed to go to? There is a larger tube in a wire loom that is not hooked up to anything. Thanks and wishing all at FTE a safe Memorial Day weekend.

May 29, 2006 | 07:56 PM

steve(ill)

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the little tube goes thru the firewall to the dash. off the one side of the tee is a 1/8 inch tube that runs behind the battery to the right fender- dont know, probably an accumulator. off the other side of the TEE is a bigger line that runs up aginst the firewall, behind the big electrical contact block toward the drivers side of truck., curves toward the front of the truck, and ties into the top of the intake manifold, right side on motor, about the center. this is probalby a 1/4 inch hose that feeds the vacuum supply to the dash.

May 29, 2006 | 08:03 PM

Fordteamone

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From: Concrete WA

Steve thanks for the fast reply. It is the small 1/8 th inch tube out the side that is open. Will look in the fender well. The in and out run part is still hooked up, so this open line is probably causing a leak and the blend door not to open. Thanks.