BRUSH 0091598 - Caterpillar

Test Procedure for Temperature Gauge Circuits
An easy test can be made to determine if the gauge works correctly.1. Make sure that the gauge is grounded. The gauge is normally grounded through the case, but put a jumper wire from the gauge ground terminal to machine ground to be sure of a good ground.2. Disconnect the wire from the sender connection of the gauge. This is the same as a very high resistance. The gauge must show a low temperature.3. Put a jumper wire from the sender connection on the gauge to machine ground. This is the same as a very low resistance. The gauge must show a high temperature.If this test shows that the gauge works correctly, check the wiring between the gauge and the sender. Also check that the body of the sender is grounded to the machine.If the gauge and wiring are good, make a check of the sender. If a sender is at a low temperature, the resistance of the sender must be high. If the sender is at a high temperature, the resistance must be low. At 38°C (100°F) the resistance of the sender must be approximately 14,000 ohms. At 160°C (320°F) the resistance must be approximately 185 ohms.The needle (indicator) for the temperature gauges can be in any position when the main power key switch is turned off. There are two different ways to check the accuracy of a temperature gauge:1. The gauge can be checked with its respective sender in water or oil at a specific temperature.2. The gauge can also be checked