VR Commodore - Fan doesn't always start when turning it on

I am wondering if anyone can help - My VR Commodore has this habbit to start the fan anywhere from immediately to 10 minutes after I started driving before it starts up. This happens both when Aircon is on or off. Quite a nasty habit, especially now in summer when it heats up and Aircon would be handy to turn on.
Also, once it is going, with or without Aircon, I can turn the fan off and back on again and it works - I cleaned out the fuses but haven't yet checked the relays.
Any responses that would assist would be appreciated.

Thanks in advance.

Roland

relays would probably be the answer, or, the Computer (eeek). Take it to an auto sparky mate.