A/C - Lack Of Temperature Control In All Modes
Article No.99-5-5
03/22/99
AIR CONDITIONING - LACK OF TEMPERATURE
CONTROL IN ALL MODES - VEHICLES BUILT
THROUGH 3/1/1999
LIGHT TRUCK:
1999 WINDSTAR
ISSUE
There may be a lack of heat control, lack of A/C control, and/or a lack of temperature control on some vehicles. This may be caused by a binding blend door or inoperative temperature control potentiometer.
ACTION
Resecure plenum stud and/or replace front A/C heater control head. This should reduce the possibility of lack of temperature control. Refer to the following Service Procedure for details.
SERVICE PROCEDURE
1. Verify the customer's concern using a climate control thermometer in one of the forced air ducts. If the customer's concern is verified, proceed with this TSB.
2. Check for smooth operation of the blend door actuator by observing the blend door actuator shaft movement. To observe, look upward from the driver's floor area with a flashlight and cycle the blend door using the A/C and heater temperature controls.
a. If the blend door actuator operation is smooth and travels through its full range of motion (approximately 90 degrees of rotation), then this TSB will not address your concern. Refer to the 1999 Windstar Workshop Manual.
b. If the door is not restricted but does not move, go to Step 4 which will address the control head itself.
c. If the blend door actuator does not operate smoothly because it binds during travel, then proceed to Step 3 which will address blend door diagnosis.
3. If the plenum retention center stud does not pass through the engine compartment bulkhead it will cause the plenum to deflect and obstruct the movement of the blend door. The blend door has to operate properly or temperature selection will be lost. To inspect the center stud position and verify that it passes through the bulkhead, look underhood near the A/C evaporator lines (Figure 1). The stud must have a nut and washer with sealer material under the washer.
NOTE
THE CENTER HEATER STUD IS ALSO USED TO SECURE THE WET COWL DRAIN TUBE.
4. Remove the front control head without disconnecting any wiring or vacuum. Check all electrical connections for proper mating and terminal push-outs.
a. If electrical repairs were performed, verify fix.
b. If no electrical repairs were made, perform "A/C Electronic Blend Door Actuator Motor System Check" as outlined in the Workshop Manual, Section 412-00, Pinpoint Test "I".
5. If climate control system pinpoint test directs you to install a new "Function Selector Switch," replace the front control head.
6. Replace front control.
PART NUMBER PART NAME
XF2Z-19980-AA Front control - Without Auxiliary A/C
XF2Z-19980-BA Front Control - With Auxiliary A/C
XF2Z-18549-AA Front Control with Heater Only
N621927-5301 Nut
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
990505AB Extra Time To Perform 0.5 Hr.
Pinpoint Test "I" (Includes
Time For Wire Repair)
990505AC Extra Time To Replace 0.2 Hr.
Front Control Head
990505A Perform Diagnostic Steps 0.3 Hr.
1-3
DEALER CODING
CONDITION
BASIC PART NO. CODE
19980 41
OASIS CODES: 208000, 208100, 208200