Help needed with A/C

[derik]

My son has a 1996 Mercury Sable that has been plagued with an A/C malfunction for over 1 year. I’m throwing this out to the populace in the hope that someone on this board may have a solution.

May 2004: cycling switch replaced at Pep Boys
August 2004: multi-function control unit replaced at Goodyear
December 2004: system recharged at Mercury dealer
May 2005: remote climate control unit replaced at another Ford-Lincoln-Mercury dealer. At first, diagnostics showed the PCM to be bad, but a new PCM did not solve the problem
June 2005: service manager at above dealer suspected interior temperature sensor bad; not replaced because the cost is $730
a/c compressor clutch failed during diagnostics (supposedly) cost $130+ to replace

After each new part was replaced, the A/C worked for about 1 day before blowing hot air again. I suspected a bad blend-door, but was told that is usually looked at first.

My son makes $14,000/year as a graduate student. As such, he can’t afford these “fixes” that don’t work. Any suggestions from the group though I realize you aren’t looking at the car?

[BillyGman]

I suspected a bad blend-door, but was told that is usually looked at first."
You sound like you know more about this than i do, since I don't even know what tou're refering to when you say a "blend door". But I'm also getting the impression by your words above, they this might not have been checked if that was the answer they gave you. they stated that it's "usualy' the first thing to be checked, but they couldn't positively state that it had been. So if you think that's what it might be, then I'd go to another dealer or garage and insist that they check that. I'm sorry, but that's all I can come up with for you.

[torinodan]

Is this a manual or electronic control system? I have the 96 Ford tech publications cd right here. More info if you need it.

Inspection and Verification
1. Verify the customer's concern by operating the manual A/C-heater controls to duplicate the condition.

2. Inspect to determine if one of the following mechanical or electrical concerns apply:
VISUAL INSPECTION CHART
Mechanical
Broken or leaking vacuum control
motor.
Broken A/C damper door switch.
Electrical Fuse junction panel Blown fuse.
Fuse 5 (15A)
Fuse 9 (30A)
Heater blower motor switch inoperative.
Circuitry open/shorted.
A/C control inoperative.
A/C electronic door actuator motor
inoperative.

[derik]

Torinodan
It's the automatic climate control system. It's just discouraging because my son has been up and down with quite a few "automobile specialists." The technician at this last dealer even got on the horn with a Ford A/C technician. So far, we seem to be up against a brick wall. Thanks for the comments and suggestions. Any others will be welcome.

Anybody know of any good automobile A/C technicians or even a training school in central Pennsylvania?

[carfixer]

Derik, it sounds like you have a warped "STRATIFICATION (SECONDARY) TEMPERATURE BLEND DOOR". It is a rather common problem that we see here in FL. Read the TSB and see if it applies to your symptoms. If so, you will need a new door. The part is really cheap (under 10 bucks) but expect labor to replace it to be around 6 hours.


TSB
02-23-6 CLIMATE CONTROL - ERRATIC OPERATION OF THE COOL/WARM FUNCTION OF THE TEMPERATURE CONTROL SYSTEM - REPAIR PROCEDURE FOR STRATIFICATION (SECONDARY) TEMPERATURE BLEND DOOR

Publication Date: November 18, 2002

FORD: 1996-2003 TAURUS
LINCOLN: 1998-2002 CONTINENTAL
MERCURY: 1996-2003 SABLE


ISSUE:
Some vehicles may exhibit constant warm air discharge from the climate control system. This may be caused by the Climate Control Stratification Door (Secondary Temperature Blend Door) which may distort and bind.

ACTION:
Replace the Climate Control Stratification (Secondary) Temperature Blend Door with a redesigned service part. The service procedure has changed as this door is now available separately versus replacing the case assembly.

SERVICE PROCEDURE

System Conditions

EATC System - EATC diagnostics may show a code B1249 or codes 022, 024 or 025. System defaults to full heat. System operates normally after running EATC on-demand self test, no concern found after performing appropriate Work Shop Manual Pin Point Test. Concern may repeat after two or more weeks.

Manual System - System has no temp control, possibly "popping" noise when changing temperature setting.

Stratification (Secondary) Temperature Blend Door Replacement

Remove the Instrument Panel. Refer to the appropriate model year Workshop Manual Section 501-12.
Remove the Temperature Blend Door Actuator. Refer to Workshop Manual Section 412-04.
The door control should now move freely. (depending on the extent of door interference, the door may not be able to be moved freely).
Inside the plenum, you will see the Stratification (Secondary) Temperature Blend Door or upper door attached to the main temperature blend door by an internal white nylon link. Disconnect the nylon link from the stratification door. Squeezing the clips together on the white nylon link should aid in removal (Figure 1).
Reach inside and remove the stratification door. Cutting the door with metal snip pliers near the pivots will provide easier removal.
Place the new door 3F1Z-19D842-AA inside the plenum chamber and slide in the large pivot point first (which is closest to you) then slide the door into position until the small door pivot point on the front side of the case clicks into place.
Connect the nylon link, reinstall the temperature blend door actuator, and instrument panel per the Workshop Manual.

PART NUMBER PART NAME
3F1Z-19D842-AA Stratification (Secondary) Temperature Blend Door

[David Morton]

Carfixer is a top knot technician with a fine sense of community. Good on you man for that TSB heads-up.

Just pop the hood and see if that A/C line going into the evaporator right after the orifice is cold when this problem occurs. If it is, the blend door TSB is probably a good spot on diagnosis. If it isn't, check the grounds.

The car does have a few years on it and too often I've seen electronic parts get replaced, sometimes more than once for the same problem, when the real culprit is a bad ground. If the A/C controls are electronic and the ground isn't good it will often fool the technician into thinking the control head, ECM, etc. is bad. A visual inspection is not always best but anything obvious like a missing battery to chassis strap, engine to chassis strap, or badly corroded ground will reveal the bad connection. Then again, how long does it take to remove the bolt or screw and file or sand the area to be sure there's a good metal to metal contact for a positive ground connection? Not much time spent and no $ at all!

[derik]

Carfixer
I was hoping you or another of the "wizards" on this board would pipe in. I was referring to this door in my initial post having read about some problems in the Windstar during the 90's. But I have to go on faith when the dealer says it was checked. Whether it really was or not is another thing.

Having read the TSB for the first time, sure sounds like the problem he is having. Works great after a part is replaced, then blows hot air again within hours or days of the repair. I would even attempt to replace the door myself. Would it be possible to copy the particular pages in the 1996 Sable service manual concerning dismantling of the dash in order to gain access to the door, and pass them on to me? Also, evacuation of the A/C system evidently is not needed in this case, correct?

Thanks again for your input.

Don

[derik]

David,
Thanks for the input. Will have to look into it.

Carfixer,
Can the function of the blend door be checked without taking the car apart? If not, I guess they really didn't check it.

My son also said that he found a blown 15 amp fuse on the floor on the driver's side. A 15 amp fuse operates the A/C system. Possible reason for the compressor clutch now not working? Don't have much recourse other than to bite the bullet and pay to have the dealer's error replaced.