PLATE-STRESS 1268132 - Caterpillar

Voltage Check on Feedback Circuit (150-1387 and 159-3665 Control Gp)
Begin by removing the storage box and covers. Refer to Disassembly and Assembly, "Storage Box and Covers (Cab) - Remove and Install".
Illustration 1 g00727424
Turn the engine start key to the ON position. Do not start the engine.
Observe the preset temperature display on the control panel for 30 seconds. Observe if "ERR 016" is displayed.
If "ERR 016" is displayed, replace the water valve. If "ERR 016" is not displayed, proceed to 5.
Monitor the voltage on wires A529-WH and A530-OR of the electrical connector with 6 pins (B) to the water valve. Do not disconnect the electrical connector. Use the multimeter probes in order to measure the voltage.
Turn the engine start key to the ON position. If the engine start key is already in the ON position, turn the engine start key to the OFF position. Then turn the engine start key back to the ON position. Do not start the engine.
When the engine start key has been in the ON position for 10 or 15 seconds, 0 volts will be present across the wires. Then, 4 or 5 volts will be present for 10 or 15 seconds. Then, the voltage may change if the ATC signals for a required position.
If the voltage changes from 0 to 5 volts, the water valve is functioning properly.
If the voltage changes partially from 0 to 5, replace the water valve.
If the voltage is constant, perform the "Supply Voltage Check".
If zero voltage is present, perform the , "Control Module - Test".Supply Voltage Check
Begin by removing the storage box and covers. Refer to Disassembly and Assembly, "Storage Box and Covers (Cab) - Remove and Install".
Illustration 2 g00601084
Right side of air conditioner and heater group (B) 6-pin connector
Monitor the voltage on wires A526-PK and on A527-BU of the electrical connector with 6 pins (B) to the water valve. Do not disconnect the electrical connector. Use the multimeter probes in order to measure the voltage.
Turn the engine start key to the ON position. Do not start the engine.
When the engine start key has been in the ON position for 10 or 15 seconds, 12 volts will be present across the wires. Then, negative 12 volts will be present for 10 or 15 seconds. If the voltage is not present, the control module is not functioning properly. Perform the , "Control Module - Test".
Else, replace the water valve if the "Voltage Check on Feedback Circuit" was performed.
Illustration 3 g00370395
(A) Opening (clockwise direction) (B) Closing (counterclockwise direction)
Visually check the rotation of the shaft on the actuator motor. Turn the engine start key to the ON position. If the engine start key is already in the ON position, turn the engine start key to the OFF position. Then turn the engine start key back to the ON position. Do not start the engine. The water valve will rotate counterclockwise for about 15 seconds. Then, the water valve will rotate clockwise for the following 15 seconds.If the actuator motor for the valve does not rotate,