Yup. That proves the high-current circuit is working. The suspects now are a defective relay, or the Engine Computer is not turning that relay on. On most cars, if you turn on the ignition switch, then unplug the two-wire coolant temperature sensor, the fan relay will be turned on by default. The Engine Computer will see the sensor circuit has a defect, and will turn the fan on just in case there is an overheating problem.
If the fan runs when you unplug the sensor, you likely do not have a problem. A lot of GM engines have to get as high as 226 degrees before the fan turns on.
If you hear the fan relay click, but the fan doesn't run, suspect the relay. Swap it with one of the other ones like it as a test.
Monday, June 12th, 2017 AT 7:56 PM