Heater and high revs
 

Hi all,

When i slide the slider button to turn my heater on, the revs jump up from tickover to around 1300rpm, this in turn is giving me rev hang on gear change, also once in a blue moon the heater will just cut out but restart if i turn the ignition off then on again, with the heater off tickover is fine and know rev hang,
The car has a good battery and air con multi plug is disconnected,
Any advice much appreaciated.

Craig.

It sounds as though the power transistor on the blower motor has failed, replacing is quite straight forward but it might be more economic in the long run to consider changing the blower motor for a low mileage or known good working one from a breaker.

Also consider servicing the idle air control valve (sounds as though it's sticking when compensating the engine load), throttle butterfly valve and housing.

The electric side of the gnition switch is another possible candidate so make sure it's returning to position II after starting the engine. Replacement is recommended if no knowledge of it being replaced