Heater fan problems

[Zsolt]

My heater fan has started acting up recently. It is also pretty cold right 
now, so it's not pleasant. The car is an '88 5ktq, and the symptoms as follow:

- the fan seem to come on by itself in ECO mode when the car is first 
started up
- in DEFROST mode it doesn't start until it starts blowing by itself (it 
used to start blowing immediately when it's pressed even cold engine)
- when the engine is re-started, the fan doesn't come on for a looooong 
time, or at all.

I am guessing it's the digital controller unit. Any BTDT?

Thanks, and Happy Holidays everybody!
ZSolt