Ford Fiesta heater continuously hot

[kickinghorse]

V reg diesel 1.8 ford fiesta - The heater/fan blows out hot air no matter what temperature setting is used. Has anyone else had this problem or know how to solve it?

[erimus1]

Sound like the heater matrix thermostat is stuck to me mate.

[RATTER14]

or cable become disconnected.

[tomtech]

if you follow the two heater pipes up from the engine they pass thru a black valve with wires plugged in. the pipes then go thru to the inside of the car. that valve is usually the first thing to pack up, ive changed a few of them. its an easy job.