[DaddysBull]

Car: 2002 Ford Taurus SES (3.0L DOHC)

It was really hot outside today and usually when that is the case I put down the windows and drive but today it was also raining so I kept the windows up and attempted to put on the air conditioning. To my dismay nothing happened. Eventually I felt some cold air (it was coming from the defrosters) but no cold air was coming out of the head vents. I played around with the different settings and I believe the feet vents are working on the feet settings but the head vents never work.

Does anyone have any idea of what is wrong or how much it will cost to fix?

 

[shoz123]

Those are all controlled by vacuum motors.

 

[the_intimidator_02]

Check for a vacuum leak. It will default to the defroster when vacuum is lost.

 

[DaddysBull]

Ok thanks for the insight. My mechanic is away on vacation so I'll have to deal without it for the next week 5 days or so but I should be ok as long as it isn't raining and I can put the windows down.

Now for almost the last 2 years the engine light has been going on and off, always for the same code P1506 which is speed density and idle air control. I had the IAC looked at and cleaned and they said it should be running normally and they said it could be a vacuum leak somewhere. You guys think there is a good chance thats all it is?

And vacuum leaks are cheap to fix right? Just get a new hose if you have to? (I only ask that because I think my dad broke it so I want him to pay for it but if not I'm going to have to and I'm strapped for cash at the moment):mellow:

 

[shoz123]

Vacuum leaks are usually easy to fix, hard to find.

On the G3s there is a hard vacuum line that runs along the cowl that then tees off to two smaller lines by the passenger strut tower. One of these lines goes into the firewall on and feeds the vacuum motors. The other goes into the passenger side fender and feeds a vacuum tank.

 

[DaddysBull]

Alright thanks for that, I'll be sure to look for it based on that description. It is safe to use the A/C even with it just coming through the defrosters correct? or will that cause issues?

 

[mh488]

Alright thanks for that, I'll be sure to look for it based on that description. It is safe to use the A/C even with it just coming through the defrosters correct? or will that cause issues?

Should be fine to use the a/c however it might frost/fog up the windshield depending on outside tempsl. I second the vacuum leak is easy to fix/ difficult to find!!

When you have the selector on windshield and the temp at cool the a/c runs to get rid of moisture, so running a/c that way is fine.

 

[DaddysBull]

Ok guys I had my friends dad look at it outside in the sun which probably wasn't the best but their garage and driveway were full but he said he didn't see a vacuum line with a leak initially and he got in the car and messed with the vents and he said that since the floor vents work on the floor setting it most likely ISN'T a vacuum leak because if it was even on the floor setting it would default to the defroster.

He said that it would be a motor behind the dash but I forget what he called it now that I am home. Does anybody know what he could be talking about. It had a weird name that I had never heard of before.

 

[KhanTyranitar]

It could still be a leak. Low vacuum can cause the defroster so revert to defrost and still allow the floor vents to work.

 

[DaddysBull]

Ugh alright well I guess I will have to get a more thorough inspection. The part he was talking about is something called a Blend Door....

 

[shoz123]

Blend door actuator. It controls the temp on cars with the automatic temp control.

 

[rickpark]

I am having a similar problem as the OP with my 2001 Vulcan, manual heater/ac controls.

Turning on AC or heat and blower results in no air coming through the vents but through the defroster vents on the far ends of the dashboard.

Does this sound like a blend door actuator problem?

TIA.

 

[sheila]

Sounds like a vacuum problem. See the posts by the intimidator 02 and shoz123 on the preceding page. Loss of vacuum, system defaults to defrost mode.

 

[rickpark]

Thanks

I pulled out my Ford service DVD and found the section on climate control.

The symptom chart for incorrect/erratic direction of airflow from the dashboard outlets sounds about right and points to a test script which has a lot of vacuum leak checks.

Sounds like it will be a tedious project unless I get lucky and find a broken/disconnected/kinked line or a bad vacuum check valve in the early steps of the checklist. Will have to break out the Mityvac.

 

[rickpark]

I pulled the vacuum connector to the vent control switch on the integrated radio/climate control panel after pulling the radio housing. With the engine running, I could not detect any vacuum from the black line so there is something wrong with the vacuum source at the other end. Will have to trace it back to see where I am losing the vacuum.

 

[Scout1]

The blend door has nothing to do with where the air comes out. It only adjust the air tempeture. Most vacuum motors in the dash are very reliable and seldom cause problems. Very good thing because they are a b....ch to get to. The good news is you said you have no vacuum at the black tube going into the firewall in the motor compartment. This will be a lot easier to find. Visually follow it as best you can. It should have a little one way valve right around where it goes in the firewall, check the other side of it for vaccum. Sometimes they fail. Somewhere around the passenger's wheel well behind the splash shield there is a "can or ball looking thing" that kind of stores extra vacuum. Famous for hoses to crack or come loose there. Good luck.

Ed

 

[rickpark]

Ed, thanks for the tips - I will be working on it this weekend and post the outcome.

 

[rickpark]

Fixed!!

I replaced the large vacuum line (the one that runs above the intake manifold near the firewall. It was pretty hardened and I suspect leaking vacuum where the check valve that connects the vacuum reservoir (yellow line) and the supply to the multi-function switch connects to that line.

 

[sheila]

Congrats! Most of those hvac vac. leaks do seem to occur underhood due to eng. heat, cold of winter, etc. Glad you didnt have to pull the dash and start troubleshooting individual vac motors and lines. Was the big line you replaced the one that originates from the ac port of the vac. manifold on the drivers side firewall? Theres also a smaller line originating from the port marked s that is prone to failure. Iirc, theyre both clipped to the cowling?

 

[rickpark]

Yes, the big one (10 mm OD).

I had to use a long piece of hose that was a snug fit to the check valve on the passenger side along with a larger ID piece to fit the larger nipple on that driver side vacuum manifold. The longer piece of hose is a snug fit inside the larger ID piece.

The original vacuum line looks like the two ends have different IDs.

I noticed that smaller line; what is it's purpose?