Car wiring diagrams: Ford Ka Heater Not Working, wiring diagram, wire wiring harness, schematic circuit diagram, wiring diagran, wireing diagram, wirring diagram, wiring daigram, wiring diagrams. Heater not working only blowing cold air. lydias. Hi All, My heaters has stopped working in my Ka, it will only blow completly cold air, i was .I ve just bought the missus a ford ka to replace the Bravo and she s loving the car so far. Only slight niggle is the heater doesn t seem to .I have a ford ka and like the heating in the summer is killing me. . i have a mk fiesta and the other .Ford Ka Heater Switch test Bad Heater Control Valve HCV Hi there i know this is an old video .