KNOB 1641398 - Caterpillar

Equipped With EMSThe hydraulic and coolant flow switches used in the EMS can be damaged if they are checked with a continuity tester or an analog type (moving needle) multimeter. Some examples of the hydraulic and coolant flow switches that could be damaged are 6N5284, 6T9315, 9J4132 or 7T2074 Flow Switch Assemblies. The steady state current rating of the flow switches used in the EMS varies between 0.01 and 0.50 Amps DC. The use of some continuity testers, such as the 8T500 or 8S4627 Continuity Tester, or analog type multimeters, can cause a momentary surge of current that may damage the flow switches. For example, the momentary rush of current through the flow switch to light a 8T500 or 8S4627 Continuity Tester can be up to 2.0 Amps. This high surge of current can cause the flow switches to become shorted or intermittent. To prevent damage, use only a digital type multimeter, such as the 6V3030, 6V7900 or 6V7070 Digital Multimeters, on the 200 ohms scale, to check the EMS flow switches. This will prevent the switches from being damaged during a test. Switches used with dash lamps on earlier machines without EMS are not effected.