1987 300SDL. I found this little doodad under the hood. It appears to be connected to my AC compressor. Also, the brand name of the compressor is Unilolo. Appears to be Japanese.

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Whatever it is, it isn't stock. The OEM compressor is a Denso and has a 3-wire plug on it up near the clutch coil.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

It's actually spelled UNICLA , this is an aftermarket compressor maker I'm guessing the black device is a rpm sensor converter or something similar.

Get the the numbers from the compressors green sticker and have a look at the sites below. Also, post any diagrams you find to help others.

Unicla International Pte Ltd
Home

Compressor - Unicla International Pte Ltd
Compressor

Unicla International Limited
https://www.unicla.hk/

Unicla - Supercool
https://www.supercool.com.au/unicla.html.

Looks like a typical YB-ROW device to me. It's quite simple really. You see, three wires enter from the top. On one side, the letters Y and B appear, while on the other side, you'll find an R, an O, and a W. In other words, I have no idea what that thing is.

__________________
1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

Please, elaborate! 😂😂😂

I can't tell for certain, but from the wires I see, it looks like the letters might indicate the color of the wire that connects there. Maybe it's a connection point. Otherwise, I don't know.

__________________
Marshall Welch
Seattle, WA
1982 300D-T

That's the tracking device. You haven't been wearing your AFDB!!! If you had been more diligent about good AFDB hygene, you would have recognized that immediately and moved it to some other persons car.

Aluminum Foil Deflector Beanie

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Where do the wires end up? Knowing where they interconnect with the harness would be an important clue. Are there any other markings on the case? Blind guesses:

- a solid state switchover relay for some purpose TBD
- a device which simulates the RPM sensor signal, to fool the Klima. I think a few of us could use such a beasty.

Did you read my post 3 above at all?

Did you supply an answer?

I was asking torsionbar to elaborate. He was on a roll with his explanation ������

I did read your post, but haven't had time to think about the car and gadget since I posted. I've been trying to get some other things accomplished today. It's gonna be Wednesday of next week before I can study on the old gal again. Work and life tends to get in the way of the "funerer" stuff.

EDIT: It is UNICLA, but dear Lord they made it hard enough to read. ��

Yes, I supplied the proper brand name and links for him to look it up.

You supplied what beyond guesses?