A/C - Reduced Vent Airflow/Lack Of Cooling
TSB 10-3-603/01/10
LACK OF NC COOLING - RESTRICTED/REDUCED
AIR FLOW THROUGH VENTS - EVAPORATOR CORE
ICING - BUILT ON OR AFTER 1/212008
FORD:
2008-2010 Crown Victoria
ISSUE
Some 2008-2010 Crown Victoria Police Interceptor vehicles built on or after 1/2/2008 may exhibit a lack of A/C cooling and restricted/reduced air flow through the A/C vents typically during extended idling conditions. This may be due to extended A/C compressor operation (lack of compressor cycling) causing icing of the evaporator core surface.
ACTION
Follow the Service Procedure steps to correct the condition.
SERVICE PROCEDURE
To service, first verify that the A/C clutch relay is operating properly and that the contacts are not sticking closed. The A/C clutch relay contacts may stick closed due to arcing. The arcing may be caused by transient voltage from the A/C clutch field coil when the relay contacts open to turn off the AC clutch. Refer to the following:
1. Monitor the powertrain control module (PCM) PIDS, ACCS and WAC. If WAC PID reads OFF, and the A/C compressor continuously operates, remove A/C relay and check for contacts sticking closed.
a. A/C relay contacts that are sticking closed will have continuity between relay pins 3 and 5.
(1) If continuity is found, replace the A/C relay.
(2) It will also be necessary to add a 400V 1.0A diode from circuit 57 BK to circuit 321 GY/WH. Proceed to Diode Installation.
b. If the A/C relay contacts are not sticking closed, then do not continue with this procedure. Perform normal diagnosis using Wiring Diagrams (WD) and Workshop Manual (WSM) procedures.
NOTE
PICTURED ON THE DIODE WILL BE AN ARROW WITH A LINE AT THE TIP (THE SYMBOL FOR THE DIODE). THIS IS IMPORTANT TO NOTE BECAUSE IT INDICATES THE DIRECTION IN WHICH THE DIODE MUST BE INSTALLED. THE DIODE MUST BE PLACED SO THAT THE ARROW POINTS FROM CIRCUIT 57 (BK) TO CIRCUIT 321 (GY/WH). REFER TO THE DIODE INSTALLATION PROCEDURES BELOW.
Diode Installation
1. Disconnect the battery.
2. Disconnect female connector C192.
3. Identify circuit 57 (BK) pin location 6 and circuit 321 (GY/WH) pin location 8.
4. Remove circuits 57 and 321 from the connector.
5. Strip 1" (25 mm) of insulation away from circuit 57 approximately 2" (50 mm) from the connector. (Figure 1)
6. Strip 1" (25 mm ) of insulation away from circuit 321 approximately 4" (100 mm) from the connector. (Figure 1)
7. Cut the butt connectors from the diode and strip approximately 1.25" (32 mm) of insulation from the cut ends of the wires. (Figure 2)
8. Twist the ends of the diode wires around the exposed wire on circuits 57 and 321. (Figure 3)
NOTE
THE DIODE MUST BE INSTALLED TO ALLOW CURRENT FLOW FROM CIRCUIT 57 TO CIRCUIT 321 (THE ARROW ON THE DIODE MUST POINT FROM CIRCUIT 57 TO CIRCUIT 321). ORIENT THE DIODE WIRES AWAY FROM THE TERMINAL ENDS OF CIRCUITS 57 (BK) AND 321(GY/WH) AS SHOWN IN THE ILLUSTRATIONS. THIS WILL ALLOW HEAT SHRINK TUBING TO BE SLIPPED ON THE WIRES.
9. Solder the diode wires to circuits 57 and 321. Use rosin core mildly activated (RMA) solder.
NOTE
DO NOT USE ACID CORE SOLDER.
10. Slip Dual Wall Heat Shrink Tubing containing hot melt wax up the terminal ends of circuits 57 and 321 over the exposed wire.
NOTE
IT IS IMPORTANT TO USE HEAT SHRINK TUBING CONTAINING HOT MELT WAX OVER A SOLDERED CIRCUIT JOINT TO CREATE A WATERPROOF AND AIRTIGHT CONNECTION. MAKE SURE THAT THE TUBING COVERS ALL EXPOSED WIRES PLUS AT LEAST A HALF INCH AT BOTH ENDS. (FIGURE 4)
11. Heat the entire length of the heat shrink tubing until the hot melted wax appears from both ends of the tubing. (Figure 5)
12. Reconnect connector C192.
13. Reconnect the battery and test the circuit for correct A/C operation.
Parts Block
WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
IMPORTANT: Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.
OPERATION DESCRIPTION TIME
100306A 2008-2010 Crown Victoria: 0.9 Hr.
Replace The A/C Clutch
Relay And Install Diode,
Includes Time To Monitor
PIDS And Check Relay
(Do Not Use With Any
Other Labor Operations)
DEALER CODING
CONDITION
BASIC PART NO. CODE
14N089 42
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