I dont know your car model well but I do know that intermittent blower operation can be related to intermittency in the ignition switch. On my 87, 260E, the power for the blower comes straight from the ignition swicth and the contacts either get burnt internally or sometimes you just have loose connections on the outside. So please check this before going downstream to either the blower motor or the CCU. Also blower motors take a lot of current and so the fuse is also special, atleast in my 87 260E, and it develops hairline cracks that can cause intermittency.

__________________
Saumil S. Patel