Measure the resistance between temperature blend door actuator C289 pin 6, circuit 436 (RD/LG) and pin 3, circuit 437 (YE/LG)
while rotating the temperature control potentiometer from full WARM to full COOL.
Does the resistance vary between 150 and 4,800 ohms?
Yes
GO to
M9
.
No
GO to
M7
.
M7 CHECK CIRCUIT 437 (YE/LG) FOR AN OPEN
Disconnect: Temperature Control Potentiometer C294c.
Measure the resistances between actuator C289 pin 3, circuit 437 (YE/LG) and temperature control potentiometer C294c pin 2,
circuit 437 (YE/LG).
Is the resistance less than 5 ohms?
Yes
GO to
M8
.
No
REPAIR circuit 437 (YE/LG) for an open.
TEST the system for normal operation.
M8 CHECK CIRCUITS 436 (RD/LG) AND 437 (YE/LG) FOR A SHORT TOGETHER
Measure the resistance between temperature blend door actuator C289 pin 6, circuit 436 (RD/LG) and pin 3, circuit 437
(YE/LG).
Is the resistance less than 5 ohms?
Yes
REPAIR circuits 436 (RD/LG) and 437
(YE/LG) for a short together. TEST the
system for normal operation.
No
INSTALL a new temperature control
potentiometer. REFER to
Section 412-04
.
TEST the system for normal operation.
M9 CHECK CIRCUITS 436 (RD/LG) AND 437 (YE/LG) FOR A SHORT TO GROUND
Disconnect: Temperature Control Potentiometer C294c.
Measure the resistances between temperature blend door actuator C289 pin 6, circuit 436 (RD/LG) and ground, and between
temperature blend door actuator C289 pin 3, circuit 437 (YE/LG) and ground.
Are the resistances less than 5 ohms?
Yes
REPAIR the affected circuit for a short to
ground. TEST the system for normal
operation.
No
GO to
M10
.
M10 CHECK CIRCUITS 437 (YE/LG) AND 438 (RD/WH) FOR A SHORT TO GROUND
Disconnect: Temperature Control Potentiometer C294c.
Ignition ON.
Measure the voltages between temperature blend door actuator C289 pin 4, circuit 438 (RD/WH) and ground, and between
temperature blend door actuator C289 pin 3, circuit 437 (YE/LG) and ground.
Yes
REPAIR the affected circuit for a short to
power. TEST the system for normal
operation.
No
GO to
M11
.
Page 35 of 47
2003 Taurus/Sable Workshop Manual
11/22/2011
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS3H/~MUS~LEN/19/...
