Ford Fairmont 1992 Problems

I ASKED Mark Lynch of Carcool for his opinion. He thought the fault could be either the ambient temperature sensor or a faulty climate-control unit itself. The ambient sensor behind the front bumper tells the climate control the outside temperature. If this goes open circuit, the control will assume that it is -50C and will switch to full heating. The climate control unit itself could have a faulty component, dry-joint in the board, or bad connection plug. Try changing the ambient sensor and clean its connector. If it fails again, replace the climate control head.