The Item is in the air intake before the air filter. It is actually down in the first plastic section of the air intake. the electrical line runs to the ezl. I have looked threw the Pelican parts catalog found nothing that resembles this item.
I would think it to be a temperature sensor or possibly an air flow sensor put I am not sure, and do not know its purpose in the system. The reason for my curiosity is due to seeking answers for incorrect readings at the EHA and duty cycle readings.

ID this car, please.

Sixto
87 300D

A picture would help. In your album it shows a 1990 420SEL so assuming this is the car.
I can't find it at pelican Parts either, I hate to send people somewhere else for parts. I did find an IAT sensor at another site, by your description I think that's what it is also:
Mercedes 420SEL IAT Sensor - Free Shipping - Bosch, OES Genuine

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sorry folks I have had my head in my back side for some weeks now, any way it is a 1991 190E 2.6

You are talking about this sensor

Ambient Air temp sensor. Helps idle control from the ECU. Normally installed in cars in cooler climates.

Ambient air temp or outside temp sensor is for the outside temp display in the instrument cluster, this is called the IAT, Intake air temp sensor.

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Yep, that's right. If faulty, get a new one from MB, mine was 12€ versus about 30 for other suppliers.

R

Intake air sensor, thank you, my car was sold threw an Alaskin dealer. but it dose help with fuel settings or strictly temp guage? how dose one test this unit for correct readings?

That's NOT the one that informs your cluster.
It's for fuel management purposes

The one for the cluster is in your front bumper and looks like a stick

Change it if it's faulty

What he said.
Shoul dbe a chart somewhere to compare the actual temp (on the bench) to a resistance it should read. If you can check that it would be better than just replacing on a hunch.

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Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold)

It's one of the cheapest sensors on that car.
Let me know what part number it has and i'll send it to you. Just pay for shipping. Wish my car had those issues