Component Tests
A/C Evaporator Discharge Temperature Sensor
Heater Core
WARNING: Carbon monoxide is colorless, odorless and dangerous. If it is necessary to operate the engine with the vehicle in a closed area such as a garage, always use
an exhaust collector to vent the exhaust gases outside the closed area.
1.
NOTE:
Testing of returned heater cores reveals that a large percentage are good and did not require installation of a new heater core. If a heater core leak is suspected, the heater
core must be tested by following the plugged heater core component test before the heater core pressure test. Carry out a system inspection by checking the heater system
thoroughly as follows:
Inspect for evidence of coolant leakage at the heater water hose to heater core attachments. A coolant leak in the heater water hose (18472) could follow the heater core tube to the
heater core and appear as a leak in the heater core (18476).
2.
NOTE:
Spring-type clamps are installed as original equipment. Installation and over-tightening of non-specification clamps can cause leakage at the heater water hose connection
and damage the heater core.
Check the integrity of the heater water hose clamps.
Heater Core—Plugged
Did the voltage continually decrease without discontinuities?
U3 CHECK CIRCUIT 776 (OG/BK) FOR A SHORT TO GROUND
Ignition OFF.
Disconnect: Blower Motor Speed Control C271a.
Measure the resistance between the remote climate control (RCC) module C228 pin 24, circuit 776 (OG/BK) and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to
U4
.
No
REPAIR circuit 776 (OG/BK) for a short to
ground. TEST the system for normal
operation.
U4 CHECK CIRCUIT 776 (OG/BK) FOR AN OPEN
Measure the resistance between the RCC module C228 pin 24, circuit 776 (OG/BK) and the blower motor speed control
C271a pin 3, circuit 776 (OG/BK).
Is the resistance less than 5 ohms?
Yes
INSTALL a new RCC module. TEST the
system for normal operation.
No
REPAIR circuit 776 (OG/BK) for an open.
TEST the system for normal operation.
Temperature
Resistance
-40°C (-40°F) 832,500-1,017,500 ohms
-20°C (-4°F)
263,100-290,800 ohms
0°C (32°F)
91,050-100,600 ohms
20°C (68°F)
35,500-39,000 ohms
25°C (77°F)
28,500-31,500 ohms
40°C (104°F)
15,300-16,900 ohms
60°C (140°F)
7,170-7,930 ohms
100°C (212°F)
1,975-2,185 ohms
-20°C (248°F)
1,130-1,250 ohms
Page 45 of 47
2003 Taurus/Sable Workshop Manual
11/22/2011
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS3H/~MUS~LEN/19/...
