Delayed blower motor...and it's freezing!

[1983 300TD]

Hi.
I just joined the fourm, and would like to thank everyone for all the helpful suggestions.

I have a 1983 300td wagon. When I leave the house in the morning, it takes 5-8 minutes for the blower motor to kick in. It doesn't matter if the fan is on high or low, and it doesn't matter if the acc is set on defrost, floor, etc. No matter which buttons I push, I get no response. Then just when I question if it's going to work at all, everything starts to work as it should. I should note that this scenario plays out most of the time, but not all the time. I have not been blowing the fuse, and I replaced the blower motor when I bought the car, two years ago. I also replaced the monovalve one month ago, as well as that foam line that runs behind the glove box. Any suggestions? Could it have anything to do with the aux. water pump?
Thanks for your time.
damon