strange dash noise

[Dottore]

Now this may be a very stupid question but here goes:

The image below is from my '88 Carrera. There is a plug in the dash immediately to the right of the steering column with two horizontal slits in it. (pretty well in the middle of the photo below)

Can someone tell me what this is? I could not find it in my manual - and I ask because there are some very strange noises (like a high-pitched coffee-grinder) coming from it whenever I start up the car. The noise seems to vary with engine speed - and has nothing to do with the heater/cooler to the right.

Any ideas?

[Dottore]

Sorry, here is the picture in smaller format.

[madmmac]

Temp sensor for auto-heat control.

[aj88cab]

I believe the source of the noise you hear is a small fan in there to circulate the air over the sensor.

[diabolos88]

does it sound like a cat dying or squealing ? if so, the footwell fans are either going or are shot already. Does the sound always come on with the engine starting or only if you have the heat switch(between the seats on the floor ) turned on?

[Dottore]

Yes it sounds like a cat dying. However the sound comes on when you start the engine - independently of the heating system. When you step on the accelerator the intensity of the sound increases and then, occasionally it disappears altogether.

[diabolos88]

the cat dyingt sound are the fans going. But what is strange is that they increase with the engine acceleration. If they start up with the engine, make sure the heater is switched to the off position. This will prevent the fans from trying to start up when the engine cranks over. You will need to replace them at the end of the day.

[snbush67]

I hate cats