Heater confusion!!

[mrandmrsbree]

Hello i am hoping somebody can answer my question! My heater in my volvo c70 2001 is playing up,after i start the car and turn it on it will stay on for about 5 seconds then go off,but if i turn the car off then turn the key one notch (not starting car) the heater will blow constantly.I checked the fuses but all ok and i actually had the heater working properly yesterday full time! Not sure if its me being stupid or there is some sort of fault,but i need it sorted as when i take my son to school in the mornings the car is cold!
Any help would be appreciated.
Thank you.

[AAnickmac]

Have you got it pushed right over to left? Auto! Or are you adjusting it via fan speed control. With car running try and wiggle fan switch see if that makes any difference. Sounds like an electrical fault to me.