Hi folks,
Can anyone help? My 2003 focus 1.8tdci ghia has an intermittent problem with the heater. At the start of each journey the temp setting works normally. After a few miles though it kicks out full heat. Stopping the engine for a few seconds then starting again usually fixes the problem for a few more miles.

Turning the climate control off and on again won't work, it has to be the ignition. Turning the engine off and on again even for a few seconds fixes it each time.

Any ideas?