SWITCH-WATER TEMPERATURE 1125475 - Caterpillar

System Operation Description:Most electrical problems are caused by poor connections. The following procedure will assist in detecting problems with connectors and with wiring. If a problem is found, correct the condition and verify that the problem is resolved.Intermittent electrical problems are sometimes resolved by disconnecting and reconnecting connectors. It is very important to check for diagnostic codes immediately before disconnecting a connector. Also check for diagnostic codes after reconnecting the connector. If the status of a diagnostic code is changed due to disconnecting and reconnecting a connector, there are several possible reasons. The likely reasons are loose terminals, improperly crimped terminals, moisture, corrosion, and inadequate mating of a connection.Follow these guidelines:
Always use a 1U-5804 Crimp Tool to service Deutsch HD and DT connectors. Never solder the terminals onto the wires. Refer to "SEHS9615, Servicing Deutsch HD and DT Style Connectors".
Always use a 147-6456 Wedge Removal Tool to remove wedges from DT connectors. Never use a screwdriver to pry a wedge from a connector.
Always use a breakout harness for a voltmeter probe or a test light. Never break the insulation of a wire in order to access to a circuit for measurements.
If a wire is cut, always install a new terminal for the repair.
The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.
Test Step 1. Check Connectors for Moisture and Corrosion
Illustration 1 g01131211
Leaky seal at the connector (typical example)
Inspect all wiring harnesses. Ensure that the routing of the wiring harness allows the wires to enter the face of each connector at a perpendicular angle. Otherwise, the wire will deform the seal bore. Refer to Illustration 1. This will create a path for the entrance of moisture. Verify that the seals for the wires are sealing correctly.
Illustration 2 g01131276
Diagram for the installation of a connector plug (typical example)
(1) Electronic Control Module (ECM) connector
(2) Correctly inserted plug
(3) Incorrectly inserted plug
Ensure that the sealing plugs are in place. If any of the plugs are missing, replace the plug. Ensure that the plugs are inserted correctly into the connector. Refer to Illustration 2.
Illustration 3 g01131019
Seal for a three-pin connector (typical example)
Illustration 4 g01131165
Seal for ECM connector (typical example)
Disconnect the suspect connector and inspect the connector seal. Ensure that the seals are in good condition. If necessary, replace the connector.
Thoroughly inspect the connectors for evidence of moisture entry. Note: It is normal to see some minor seal abrasion on connector seals. Minor seal abrasion will not allow the entry of moisture.If moisture or corrosion is evident in the connector, the source of the moisture entry must be found and the source of the moisture entry must be repaired. If the source of the moisture entry is not repaired, the problem will recur. Simply drying the connector will not fix the problem. Check the following items for the possible moisture entry path:
Missing seals
Improperly installed seals
Nicks in exposed