This was demonstrated to me by the mechanic at Borghi's after I had burnt out the circuit board and was part of the incentive to change my dash. When the fan is running at high speed and you turn the engine off you see the various dash warning lights fade slowly because the spinning fan motor becomes a generator and feeds power back into the system.
I wonder if that was the reason they poked these two diodes (on later cars) into the high/low motor feeds, in an ‘attempt’ to suppress some of the motor’s back EMF and protect the PCB?
![[Linked Image]](https://tm-img.com/images/2024/03/03/fan-diodes.jpeg)
