The computer grounds the fan relay in order to energize it. If the fan comes on, when you disconnect the CTS, at least the computer knew you unplugged that sensor.
The info says, over 30 mph, the pcm will disconnect the fan relay ground as long as the ac is not turned on and the engine temp is below a certain temp, 220 something, I'd have to double check the temp.
If you disconnect the cts, the fan should run. If the ac is on, the fan should run. If you use a jumper to access codes, key on, the fan will run. I'd check everything before I suspected the computer.
Thursday, September 3rd, 2009 AT 3:33 PM