Stuck on defrost?

Hello, This guide can help with instructions below to show you how to fix it as well. https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position Pinpoint Test A: Incorrect/Erratic Direction of Airflow From Outlet(s) Normal Operation Under normal operation, the function selector switch is provided vacuum from the engine. When a position is selected, vacuum is applied to the desired vacuum control motor that is connected to the mode door you want to control. Possible Causes Function selector switch Heater control valve Vacuum control motor Stuck or bound linkage or door Leaking or plugged vacuum hose PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLET(S) A1 CHECK THE SYSTEM AIRFLOW Key in ON position. With the engine running, adjust the blower motor speed to maximum. Check for correct airflow in each function selector switch position at engine idle and during engine acceleration. Is there airflow only from the defroster outlets under all conditions? Yes: GO to A2. No: GO to A8. A2 CHECK THE VACUUM SUPPLY LINE FOR OBSTRUCTIONS NOTE:The 2 vacuum lines to the vacuum reservoir tank are not interchangeable. Fig. 4: Disconnecting Vacuum Lines From Vacuum Reservoir Tank

Disconnect the vacuum lines from the vacuum reservoir tank. Connect the special tool to the vacuum supply line and try to pull a vacuum. If the special tool can pull a vacuum, the vacuum supply line is plugged. If the special tool pulls a partial vacuum, the vacuum supply line is restricted.

Is the vacuum supply line plugged or restricted?

Blows out the defroster only

check for a vacuum leak first then check to see if the ocntrol head is sending vacuum to one of the motors on the heater. i think it is on the drivers side. the pic shows what it looks like. the door may be stuck as well so see if it will move with it on heat.

This guide will help you

https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position

Check out the diagrams (Below). Please let us know what you find.

I hear my fan running, but none of the vents have any air coming out. (dead battery this morning. related?)

2002 4.0 L 81K miles Automatic, A/C

[quote:46bf3f6854="donsranger"]I hear my fan running, but none of the vents have any air coming out. (dead battery this morning. related?)

2002 4.0 L 81K miles Automatic, A/C[/quote:46bf3f6854]

Hello !!

Did you find why your battery get drained?

did you "jump-start" your truck?

If so, the "weak" battery won`t have enough "juice" to full power the blower....

did you "hear" the blower strong or weak?

anyhow check the cabin filter (some times get "clog") and the blower wont work efficient.

let us know we will be here for any question you have.

BTW Thanks a Lot for your Donation!!

good luck!

[quote:19200f4c2d="fisherman"][quote:19200f4c2d="donsranger"]I hear my fan running, but none of the vents have any air coming out. (dead battery this morning. related?)

2002 4.0 L 81K miles Automatic, A/C[/quote:19200f4c2d]

Hello !!

Did you find why your battery get drained?

did you "jump-start" your truck?

If so, the "weak" battery won`t have enough "juice" to full power the blower....

did you "hear" the blower strong or weak?

anyhow check the cabin filter (some times get "clog") and the blower wont work efficient.

let us know we will be here for any question you have.

BTW Thanks a Lot for your Donation!!

good luck![/quote:19200f4c2d]

Hey, I got it to work! I won't say I "fixed" it though. Something happened to the circuit I added for trailer brakes last summer. The trailer brake indicator light wasn't coming on when I stepped on the brakes when I had the problem. I pulled and checked all the fuses and when I put it back together, The brakes worked and also the air came out good. (the blower was running strong before, just not coming out). I figure something was loose electrically in that circuit that controls the air vents? I never had to dig into it, but I'd like to understand it. I thought the controls were vacuum, but is there an electrical component too? If you can, let me know and Thanks again. Don

By the way, no dead battery now that it's fixed. I'm assuming that was some malfunction with my trailer brakes.

Had fluid leaking into passenger floorboard several months ago, only when defroster was running, & only occasionally. (Assumed heater core was going out?) Last week, upon turning on heater, there was a constant noise from behind the glovebox, that sounded like a leaf or something stuck in the fan, & within 15 minutes, the heater started blowing cold. Have read that it is common problem on these trucks with the blend door breaking (fixed w/heatertreater). Temp gauge working normally, A/C ok, nothing leaking in floorboard at present, just no heat & the clicking noise when fan is on. Is this the blend door prob, or the actual heater core itself, or something else?

The blend door actuator would not cause the air to become cool, it would simply block the airflow to certain areas of the vehicle. The blower motor is what you may be hearing, or you may have two seperate issues altogether.

As for the coolant leak, check your hoses from the radiator all the way into the engine compartment and check for any loose fittings/cuts/etc.. Check around the heater core hoses to see if they are loose or damaged.

the ac &heater only blows air from the defrost

No, where would i find the vacume leak at? How would i go about fixing it? Any help would be greatly appreciated. Thank you.

No, there has been no work of any kind done on the truck. I would like to do the work myself if i can so if you can lead me in the right direction i would be very grateful.

The selector switch for the A/C vent is inop. Only blows out defrost no matter what position the switch is in. Truck was recently in body shop for significant front end damage. Vacumn line to big round vacumn cannister is melted shut.
Cannot find where line goes.

I know the selector swicht is vacumn operated. Where are the lines located and how would I go about troubleshooting the problem?

The big ball is a resevoir. Should have a feed line from engine and another that goes to the interior. Repair where either is damaged. if it persistes the resevoir may be damaged from accident

My heat control is stuck in defrost. I cannot change it to anything else. How do I fix it?

I believe you are dealing with a vacuum leak. The vent doors that direct air flow are actuated by vacuum. If there is a leak, the default is defroster. Check under the dash for leaks. If you are luck, with the engine running, you may hear a hissing sound where the leak is.

Check that and let me know what you find.

Joe

My heater/ac control is stuck in defrost it will not change to vents or the floor. It has a performance suspension and (2) hard 5/32" vacuum lines that come out of the glove box through the firewall to the engine compartment have been cut and do not hook to anything. I'm thinking they took out the valve, actuator or whatever it was there original to make room for the suspension. What do these (2) coming into the engine go to?

the vacuum line supplies vacuum to heater control so it will switch the vacuum motors to the desired position. This guide will help you fix it

https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position

Check out the diagrams (Below). Please let us know what you find.

Hi I have a 2000 Ford Ranger 4x4 - My A/C and Heat is working fine but when I want to use the incabin vents nothing comes out - it only comes out of the defrost and floor both heat and A/C - any ideas???

Could be the controller or actuator. The actuators/doors are vacuum controlled.

when i change selector knob... only setting for defrost blows air out. Fan works fine and i can tell air cond. is on but its like passage is block or not opening?

check for vacuum leaks check vacuum source

Jack you nailed it. I had removed a vacume line when replacing plugs last week. Thanks so much! This site is awesome!

you can move the vent control knob to all the other positions and it still comes out of the defrost vent

Without any tests to interpret, the most likely suspect is a defective actuator. My cousin had two Rangers, and both had problems with them. We never took one apart to see if it could be repaired. He took both trucks to a repair shop to have those actuators replaced, so I can't tell you what is involved either or if it's something a competent do-it-yourselfer can handle. You might consider getting a copy of the manufacturer's service manual and reading through the replacement procedure to see if it's something you want to pursue.

That's for the electronic actuators. If you have the more common, and more reliable vacuum actuators, those will be spring-loaded to default to the defrost position when vacuum is lost, as in a broken or disconnected vacuum hose. That's for safety. Your feet might freeze, but your windshield will be clear. Look on the vacuum hose routing diagram on the sticker under the hood to see if they show a small vacuum hose going to a storage canister, then through the firewall.