2004 S40 ccm problems

[LasseNanti]

Someone please help before i set my car on fire. Ccm not working properly. One side blows cold air and the other side blows hot air. I have no control over where the air blows. Sometimes the sides change. Sometimes it blows hot on both sides. Sometimes cold. Volvo dealer said i had a shortcircuit somewhere. But where??? I have tried diconnecting seat heater module. No luck. I tried another used heater module. No luck. I think all the dampermotors work because sometimes they redirect the airflow and the heat. So IF i do have a shortcircuit, where is it more likely to be??? Wires? Connectors? Ccm? Dampermotors?
Please help.