I have some Bluetooth OBD2 adapter and I use it with Torque Lite application on Android phone. I believe another application will be needed. Can you command the duty cycle through Class 2 serial data? I would be glad to know how to do this; I have seen your thread on this subject and I wanted to learn it for another project (PCM and instrument cluster bench tester).
Torque Lite does not permit the addition of custom PIDs. At first look it appears to but in practice I have found it would not work. Torque Pro DOES allow for custom PIDs and has arguably the most powerful offering of equation functions but lacks in ease of data gathering and analysis.
The Car Scanner app does a good job of recording and graphing data parameters right within the app and can also export the recorded data to a few different formats. Attached is a file of the fan parameters and a couple more for import to Car Scanner. (Rename the file from a .txt file to a .csv file type)
Here is a short display of 7 minutes at startup of my 2002 4.2 Trailblazer. It can be seen that the desired fan speed never changes (stays at 496 rpm). At first the fan does the normal high rpm as the clutch has fluid accumulated in the working chamber. As the vehicle warms the idle and the resultant fan speed drop slowly. Before the idle comes down fully I rev the engine to approximately 2000 rpm and hold it so the fan clutch fluid will be pumped into the reservoir and out of the working chamber. I then release the throttle and the idle settles to about 600 and the fan speed settles down to about 720. After about a minute I again raise the throttle to about 2000 and it can be seen that the fan speed raises to about the same rpm it had settled out to previously 2000 engine rpm indicating most of the fluid has been retained in the reservoir.
Yes, the fan clutch can be commanded to operate at various percentages of clutch applications through PWM instructions through the class 2 network. This is how the Tech 2 scantool does all its 'magic', through class 2 commands. However, being a fluid coupled device the control is quite limited. I have observed that while an increase in speed is quickly achieved, the opposite, a reduction in speed is quite slow as the fluid needs to pump out of the working chamber and back into the reservoir. I have also observed that lower levels of PWM have largely no effect. Since all my testing has been on used fan clutches, 3 so far, I suspect what I may be seeing is the result of the control valve either not fully seating or perhaps being held slightly open by detritus in the fluid. In this screenshot
I did not command the fan here in any way.
I currently have a PCM, a BCM, and a cluster on my workbench. Looks horrific but it is just for experimenting...