I’ve read through many posts on heater issues but haven’t found one with these symptoms. If the dials are at 0 it’s cold, but one notch up and it’s like a furnace. The heater and fan controls in the rear also don’t function at all and it’s permanently blowing hot out of the centre vents. On the scanner the rear heater control registers no resistance. All the fuses check out ok, and the water heater control valve looks to have been recently replaced.

Can anyone enlighten me?