diagnosticator
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« Reply #1 on: November 03, 2012, 07:09:58 AM »
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It is normal for the right side condensor fan to run when the A/C compressor is active. The left side fan will not run unless the upper coolant temp sensor and or the lower rad hose coolant temp sensor indicate the coolant temp is higher than the maximum operating temp setpoint. The sensors are not switches, they are temp dependant resistors. The sensor resistance decreases as temp increases, resulting in the temp voltage from the sensor to increase with rising temperature. The ECU provides the sensor with +5vdc supply voltage, and the return voltage back to the ECU increases up to ~ 4.9 vdc at the max temp signal from the sensor. The ECU turns the rad fan on at some increased sensor voltage/temp signal. <+~4.9 vdc. The rad fan does not run most of the time. It will only start up when idling in traffic, at lights, is hot weather, with the temp gage above the normal runnign temp.
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