[DSG2003Mach1]

how are you sure youre getting high speed and not low would be my biggest question? Would suck to be chasing it backwards. I think Id grab a test light or volt meter and check the voltage at the fan connector at low and high speed turn on temps just to be 100% sure the low leg isnt getting power.

I dunno if that fuse is pre or post CCRM. I would try to find a pinout for the CCRM (the service manual I acquired doesnt have the wiring portion sadly). Then check when conditions are correct for low speed and see if the pins into the CCRM that should trigger low speed are getting voltage. If they are then you check the appropriate pin(s) coming out of the CCRM. Then you just keep moving up or down the line based on where you lose power.