As for the lower rad hose sensor, the DME is not seeing the disconnected sensor as reading a "low temp" but as "disconnected" and would then likely run the fan as a failsafe. I didn't spend a lot of time checking, but with the coolant sensor disconnected the fan ramped up to about 1/2 speed (DME still knows engine temp) and with the A/C sensor disconnected ramped up to high. Both ramped back down when re-connected. What is the reason for wanting adjustable active fan control ??

For my 2001, the disconnected rad hose sensor caused my Foxwell to show the temp as -54*F. Maybe the ECU considers this as disconnected.

[mention]workingonit [/mention] i think replaced both his fans with one electric akin to e seventy.

So he uses speed control to get an appropriate amount of air moving as needed. I don't remember if he automated the speed or it's based on temp reading.

all-electric fans on my pre-facelift E53
 

In 2021, just after I swapped cars for the E53, I had to replace the viscous clutch fan, because the clutch was going out, and the blades were deteriorating. I used a 3000cfm aftermarket electric fan (brushed) and a thermostatic switch + override switch to switch it on, at first, then added a speed controller (for brushed fans) in-line, so I could control the fan speed from zero to 100%, as needed, from my driver's seat. Never touched the Auxilliary fan, which was working fine.

But, three years later (in 2024), the Aux fan quit working, and I installed a TYC fan in its' place. All is well, now.