Testing the Refrigerant Compressor Protection Module{1408, 1802} Caterpillar

Testing the Refrigerant Compressor Protection Module{1408, 1802}

Usage:

Engine:: 3516B (S/N: MSK1-UP); C175-16 (S/N: A7B1-UP)
Excavator:: 320C (S/N: GAD1-UP; SAH1-UP; TBR1-UP); 320D (S/N: BZF1-UP; GKS1-UP; SRT1-UP; BWW1-UP; EAX1-UP); 322C (S/N: M2H1-UP; BYL1-UP; C3R1-UP; LAR1-UP); 324D (S/N: JGK1-UP); 325C (S/N: M2K1-UP; G1L1-UP; S3M1-UP); 325D (S/N: C7K1-UP; C8L1-UP; C9M1-UP); 330C (S/N: B1K1-UP; B3M1-UP; B4N1-UP); 330D (S/N: E4K1-UP; H3K1-UP; L2K1-UP); 5130B (S/N: 4CS1-UP); 5230B (S/N: 4HZ1-UP)
Forest Machine:: 324D FM (S/N: JKR1-UP; JLS1-UP)
Industrial Tractor:: TK371 (S/N: WBG1-UP); TK381 (S/N: WBH1-UP)
Track Feller Buncher:: 1190 Series II (S/N: BZK1-UP); 1190T Series II (S/N: BZL1-UP); 1290T Series II (S/N: BZM1-UP); 1390 (S/N: B3F1-UP); 2290 (S/N: P2D1-UP); 2390 (S/N: P3H1-UP); 2391 (S/N: P4K1-UP); 2491 (S/N: P5J1-UP); 2590 (S/N: P6B1-UP); 511 (S/N: 5111-UP); 521 (S/N: 5211-UP); 522 (S/N: 5221-UP); 532 (S/N: 5321-UP); 541 (S/N: 5411-UP); 551 (S/N: 5511-UP); 552 (S/N: 5521-UP); TK711 (S/N: 1011-UP); TK721 (S/N: 1021-UP); TK722 (S/N: 1031-UP); TK732 (S/N: 1041-UP); TK741 (S/N: 2021-UP); TK751 (S/N: 3011-UP); TK752 (S/N: 3021-UP)
Wheel Feller Buncher:: 533 (S/N: CDR1-UP); 543 (S/N: ASJ1-UP); HA770 (S/N: HAB1-UP); HA771 (S/N: HAF1-UP); HA870 (S/N: HAE1-UP); HA871 (S/N: HAG1-UP); TK370 (S/N: WBD1-UP); TK380 (S/N: WBE1-UP)
Motor Grader:: 120K (S/N: JAP1-UP); 12K (S/N: JJA1-UP); 140K (S/N: JPA1-UP); 160K (S/N: JBP1-UP)
Off-Highway Truck/Tractor:: 770 (S/N: BZZ1-UP); 772 (S/N: RLB1-UP); 773F (S/N: EED1-UP); 777D (S/N: DCB1-UP); 777F (S/N: JRP1-UP); 784C (S/N: 2PZ1-UP); 785C (S/N: APX1-UP; 5AZ1-UP); 785D (S/N: MSY1-UP); 789C (S/N: 2BW1-UP); 793C (S/N: CBR1-UP; ATY1-UP); 793D (S/N: FDB1-UP); 797B (S/N: JSM1-UP)
Quarry Truck:: 775F (S/N: DLS1-UP)
Pipelayer:: 583T (S/N: CMX1-UP); 587T (S/N: FAT1-UP)
Track-Type Tractor:: D10R (S/N: 3KR1-UP; AKT1-UP); D10T (S/N: RJG1-UP); D11R (S/N: AAF1-UP; 9TR1-UP; 9XR1-UP; 7PZ1-UP); D11T (S/N: GEB1-UP; TPB1-UP; DDD1-UP; RAL1-UP); D8R (S/N: MEJ1-UP; RJM1-UP; 9EM1-UP; T5X1-UP); D8T (S/N: J8B1-UP; KPZ1-UP); D9R (S/N: JJB1-UP; ABK1-UP; ACL1-UP; WDM1-UP); D9T (S/N: RJS1-UP)
Wheel Tractor-Scraper:: 621G (S/N: DBB1-UP; MSE1-UP; CEN1-UP; ALP1-UP; CEP1-UP); 623G (S/N: DBC1-UP; CES1-UP; ARW1-UP; CEW1-UP); 627G (S/N: DBD1-UP; AXF1-UP; CEX1-UP; CEZ1-UP); 631G (S/N: DFA1-UP; AWK1-UP; CLR1-UP; CMT1-UP); 637G (S/N: CEH1-UP; CEJ1-UP; DFJ1-UP; AXT1-UP); 651E (S/N: 4YR1-UP; 5XR1-UP; 89Z1-UP); 657E (S/N: 5YR1-UP; 6PR1-UP; 6TR1-UP; 7KR1-UP); 657G (S/N: W1B1-UP; W1C1-UP; W1E1-UP; A4G1-UP)

Introduction

This Special Instruction will provide a procedure to perform functional tests before replacing the 169-7443 On Delay Timer As or the 338-1942 On Delay Timer As . The 169-7443 On Delay Timer As or the 338-1942 on Delay Timer As can also be referred to as the compressor protection module for the compressor. The compressor protection module contains a delay timer in order to protect the compressor from the following conditions:

High refrigerant pressures
Low refrigerant pressures
Incorrect system voltage
Excessive current

The delay timer prevents premature wear of the compressor when the air conditioning or the electrical system is not functioning correctly. Perform the following checks and troubleshooting procedures before replacing any parts. If the existing on delay timer fails the functional test, replace the timer. The installation procedure for a new 344-2689 Relay Kit follows the testing section of this Special Instruction.

Important Safety Information

Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs.

A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools in order to perform these functions properly.

Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard.

Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, a work method, or operating technique that is not specifically recommended by Caterpillar is used, ensure that it is safe for you and for other people to use.

Ensure that the product will not be damaged or the product will be made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.

Parts Required

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Table 1
Quantity	Part Number	Description
1	344-2689	Relay Kit

Check Electrical Connections

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Illustration 1	g01519961
Typical schematic of a circuit for a compressor

Verify that the air conditioning clutch engages when the machine is turned on and the air conditioning switch is turned to "ON". An audible click should be heard after the air conditioning switch is turned on. This audible click should not occur until 15 to 30 seconds after the air conditioning is turned on.

Ensure that the connectors are tightly connected. Also check that the connectors are secure at the following locations:
- Compressor protection module
- Low-pressure switch
- High-pressure switch
- Coil for the clutch for the air conditioning compressor

Clean the connectors of the circuit. Refer to Illustration 1.

Check For Input Signal From Air Conditioning Pressure Switches And The Thermostat Switch

The compressor protection module should prevent engagement of the clutch for an unlimited period if the low-pressure switch, the high-pressure switch, or the thermostat switch is open. Perform the following tests:

Measure the resistance between pin 1 and pin 2. The resistance should be below 10 ohms. If the resistance is above 10 ohms, perform step 1.a and step 1.b.
1. Test for a proper ground to the compressor protection module.
1. Check the refrigerant system for the air conditioning and check the pressure switches for the air conditioning. Refer to Testing and Adjusting, SENR5664.

Check Ground

The compressor protection module will prevent engagement of the clutch for an unlimited period if the circuit has an inadequate ground. Test for the following condition:

The resistance between Pin 2 and chassis ground should be 0. A high resistance is an indication of a bad ground. Inspect and repair the harness if the harness has a bad ground.

Check The System Voltage From The Air Conditioning Switch

The compressor protection module prevents engagement of the clutch for an unlimited period under certain electrical conditions. Test for the following conditions:

The voltage at pin 4 should be between 18 V and 32 V. Perform Step 1.a and Step 1.b if the voltage to pin 4 is outside of this voltage range.
1. Verify that the air conditioning switch is turned on and that the circuit breaker or the fuse for the air conditioning is intact.
1. Verify the proper operation of the batteries or alternator.

Check For Voltage Output From Pin 3 To Compressor Clutch

All other tests should be performed before performing this test. Test for the following conditions:

Start the machine. Turn the air conditioning switch to the "ON" position.

The voltage between pin 2 and pin 3 of the compressor protection module should be between 22 and 35 V within 30 seconds after the air conditioning switch has been turned "ON". The delay prevents rapid engagement of the clutch for the air conditioning compressor and premature failure of the compressor. If system voltage is not present after 30 seconds, the system may be cycling normally under a low load by the thermostat. If all other function tests indicate normal operation, the compressor protection module may have failed. Replace the module and verify that the new module turns on the air conditioner clutch.

Note: If the equipment passes all of the functional tests, then the compressor protection module is functioning normally. The air conditioning is not operating due to a fault in a different part of the system for the air conditioning. Some other possible faults may include the following:

Fault in the harness between compressor clutch and the module
Failed compressor clutch
Excessive heat load on the air conditioning during machine operation
Dirty condenser coil or air filter
An incorrect level of charge of the refrigerant

Note: Refer to Testing and Adjusting, SENR5664 for assistance in troubleshooting the HVAC system.

Rework Procedure

Locate the compressor protection module. The protection module should be located with the Air Conditioning compressor.

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Illustration 2	g02271334

Disconnect the electrical connection, remove the retaining bolt, and remove the compressor protection module.

Identify which connector pin location the wires are in on the existing connector. Label wires with corresponding pin location as 1, 2, 3, and 4.

Remove the plug-connector from the existing harness and cut off the existing sockets of the wires.

Strip each wire back and use a 239-5260 Crimp Tool to install a 9X-3402 Connector Socket onto each wire.

The wire numbering is the same, but the relative positions on the connector have changed. Install the new sockets into the new 230-5008 Connector Plug As in the following order:
- Wire 1 from existing plug-connector into position 1 on the new plug-connector.
- Wire 2 from existing plug-connector into position 2 on the new plug-connector.
- Wire 3 from existing plug-connector into position 3 on the new plug-connector.
- Wire 4 from existing plug-connector into position 4 on the new plug-connector.
Note: The sockets will "click" in the plug-connector when the sockets are correctly installed. Ensure that the sockets are correctly installed by gently pulling on the sockets and making sure that they do not come out of the connector.