So I have a P0526 code that started back when the truck broke its driveshaft the first time. I've replaced the fan clutch but no luck. Code has come back.
Clutch is plugged in just fine... not sure what else might be the issue.
You need your scan tool to observe the fan speed in the PCM ENG 2 data list. It should show the sensor turning on and off. You can also test the voltage of each circuit at the harness on the fan shroud with the ignition on but engine off and turning the fan by hand. The relay could also be bad at the fuse box. Most likely the harness is bad or a wire has been grounded within the circuit.
I'd first probe the plug at the fan shroud to make sure its got the proper grounds, voltages and connections. Can you tell if your fan is turning on and off? Is it stuck on, or stuck off?