PLATE 1103122 - Caterpillar

Table 6
Required Tools
Part Number Description Quantity
146-4080 Digital Multimeter (RS-232) 1
Illustration 6 g01069275
Typical Electronic Control Circuit for the Heater Valve
(1) Electronic controller
(2) Deutsch connector (2 pin)
(3) Deutsch connector (6 pin)
(4) Deutsch connector (3 pin)
(5) Electronic water valve assembly
(6) Electronic blend door actuator
(7) Motor for the electronic blend door actuator
(8) Feedback potentiometer for the electronic blend door actuator
(9) Potentiometer assembly (temperature control)
(10) 24 VDC power supply from blower motor breaker
(11) Deutsch connector (12 pin)
Turn off the power supply.
Disconnect Deutsch connector (11).
Hook the multimeter leads to pin (1) and pin (2). Set the multimeter to DC voltage.
Turn on the power supply. The multimeter should read approximately 24 VDC.
Turn off the power supply.
Reconnect the Deutsch connector (11) at electronic controller (1).
Disconnect Deutsch connector (4).
Connect the multimeter leads to pin (A) and pin (C) on the Deutsch connector that is on potentiometer assembly (9). Set the multimeter to read ohms. The multimeter should read 5000 500 ohms.
Connect the multimeter leads to pin (A) and pin (B) on the Deutsch connector that is on potentiometer assembly (9). Turn the knob on the potentiometer assembly (9). The resistance should vary smoothly.
Reconnect Deutsch connector (4).
Disconnect Deutsch connector (3).
Connect the multimeter leads to pin (3) and pin (5) on the Deutsch connector that is on electronic blend door actuator (6). Set the multimeter to read ohms. The multimeter should read 10000 1000 ohms.
Connect the multimeter leads to pin (1) and pin (2) on the Deutsch connector that is on electronic blend door actuator (6). Set the multimeter to DC voltage.
Turn on the power supply.
Turn the knob on the potentiometer assembly (9). The multimeter should read either −11 to −12 VDC or the multimeter should read 11 to 12 VDC while the actuator is rotating. The multimeter should read 0 VDC after the motor has stopped rotating.
Turn off the power supply.
Connect two wires to a remote 12 volt DC power supply.
Connect one wire to pin (2) on the Deutsch connector that is on the electronic blend door actuator (6).
Touch the other wire to pin (1) on the Deutsch connector that is on electronic blend door actuator (6) in order to pulse motor (7). The motor should turn clockwise or counterclockwise. The polarity of the motor determines the direction of rotation. Note: Do not pulse motor (7) for more than a fraction of a second. If you supply power for a longer period of time you may damage the actuator.
Disconnect the test equipment and reconnect Deutsch connector (3).
Disconnect Deutsch connector (2).
Rotate the potentiometer assembly (9) to full cooling. Note: The actuators must be given 60 seconds in order to completely stroke.
Connect the multimeter leads to pin (1) and pin (2) on the Deutsch connector that is on the electronic water valve assembly (5). Set the multimeter to read DC voltage.
Turn on the power supply.
Turn the knob on potentiometer assembly (9). The multimeter should read −11 to −12 VDC or the multimeter should read 11 to 12 VDC while the actuator is rotating. The multimeter should read 0