heater blowermotor

i have an 89 probe lx and the heater blower will not come on until the temp in the car is around 55-60 degrees.i drive about 40 miles one way to work and occasionaly it wont come on until i get in the parking lot. i can put it on outside air and driving will force enough warm air to keep it defrosted but i still freeze coming in. has anyone had anything like this happen? i have already switched the control head-it is electric not vaccum. and you can hear the switch click on when you adjust the speed control . any help would be appreciated