F355 HVAC question

I have a '99 f355 spider. The heater is stuck on HOT. No matter what I do. A/C works but fights against the hot air. The stepper motor is not driving the water valve. Does anyone know how I can test this thing? It is a 5 wire type. I have it out of the car. I have a multimeter. I hope it's the motor and not the ECU. Speaking of the ECU. Where is that bugger? I have swapped out the control module on the center console. No Help. Checked all the fuses. all the obvious stuff. One final note. I hear there are some other part number stepper motors that will work with some modifications. I think Ferrari wants a wad for that. It's a BOSCH part. I would appreciate any feedback on this.

 

Got it, thanks. I'm still trying to find where the ECU is. Does it have a control panel on it? I'm going to try that Saab stepper motor. The valve itself is fine.Since I have no idea how to test the one I have out of the car. Looks like it's about $140. Not bad.
Also, any hidden fuses in the HVAC system? Sure would be nice to actually be able to control the heat without having to manualy go turn the heater valve.