Black knob on dash

[Craig1.4T]

I recently bought a Bravo Dynamic 1.4T. At the front of the dashboard there is black knob. I tried to press it when the mother-in-law was in the passenger seat, but unfortunately it is not an ejector seat! I am assuming it is some kind of sensor, anyone shed any light?

 

[Sabre 23]

Automatic headlight sensor.

Mark.
New Bravo (B2) 1.4 T-Jet Active 150, silver, 57 plate.
Council estate lad.
And proud of it!
A battle of wits with the unarmed is no fun!

Member of the Guild of Experienced Motorists. Lapsed.

 

[Karl]

If only it was an ejector seat id have one for the Mrs....

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[Sabre 23]

The Automatic Headlight Sensor is not in a convenient enough position for an ejector seat trigger!!

Mark.
New Bravo (B2) 1.4 T-Jet Active 150, silver, 57 plate.
Council estate lad.
And proud of it!
A battle of wits with the unarmed is no fun!

Member of the Guild of Experienced Motorists. Lapsed.

 

[Anonymous]

The headlight sensor is on the windscreen above the rear view mirror. I tested it by covering it and the headlights came on.

 

[andyb76]

the automatic wiper sensor if it has automatic wipers is normally at on the dash by the windscreen

 

[Anonymous]

It does have automatic wipers aswell. I assumed there would be a rain sensor in the windscreen for that. So how does it sense rain then?

 

[andyb76]

im sure the little black knob thing you call it is the sensor as if your window smashed and you needed a new one then it would be really expensive if it was built into the screen

 

[Anonymous]

I believe you, I'm just curious as to how it would work being inside the car.

Thanks for everyones comments.

 

[Anonymous]

You shout "IT'S RAINING" and the wipers start.

The rain sensor is, I'm sure, behind the interior mirror, just above the fixing point.

 

[Anonymous]

Well that's what I thought. So what the hell is this thing?

 

[Sabre 23]

Rain sensor, page 58, fig 51 in the manual.

Guess I was wrong about the dash bulge being the headlight sensor. The manual neither shows the sensors position, nor does it show the bulge or explain its function.



If it has one!!

Mark.
New Bravo (B2) 1.4 T-Jet Active 150, silver, 57 plate.
Council estate lad.
And proud of it!
A battle of wits with the unarmed is no fun!
Member of the Guild of Experienced Motorists. Lapsed.

 

[Anonymous]

Rain sensors work by putting (infra red) light into the windscreen and measuring what comes out a bit farther down. The light bounces down the inside of the windscreen, a bit like an optical fibre. If rain falls on the windscreen, it allows the light to leak out (change of refractive index locally)so less gets to the other end of the sensor. The wiper is triggered and it clears the rain off the sensor and off we go again. The sensors are bonded to the inside of the windscreen, usually behind the mirror. Sometimes they get triggered by strong sunlight if the sun goes behind a cloud.

Does your car have climate control? If so this knob of yours may be a sunlight sensor. They usually look like little domes and are on top of the dash. They are transparent to infra red. No idea why they are needed though as temperature sensors are fitted elsewhere. You don't get them with straightforward air-conditioning, only auto climate control systems

 

[Craig]

Yes it has dual-zone climate control, so it is actually a light sensor which someone said before, but not for the automatic headlights.
Well, thanks for the detailed explanation of how the rain sensors work!