The blower receives power at all times from the indvert fuse in the LH underhood fuse block, and is grounded at G204. The heater/ac programmer provides speed request input to the blower motor, in response to bus messages from the climate panel. Does the fan speed respond to changes when the system is in key on operation, and then go to a default speed when the key is turned off? To isolate it you could disconnect the AC programmer blue connector C2, taking away the speed input to the blower. If the blower still operates at this point, it is internal logic that powers the blower, and I would suggest that it is faulty. The programmer is on the RH side of the instrument panel, and you may be able to get the connector with just removal of the lower insulator. In extreme case, it may require removal of the I/P compartment(glove box).