VNL780 Coolant sensor and switch

Can anyone tell me what this is in the picture? It's mounted on the passenger side frame under the hood, looks like switch with two harness one wire goes to the top of the radiator and a sensor with one harness I believe it goes back to the Transmission.

 

I wish someone who has the same kind of truck with the same thing on it can tell me what it is. My truck is a 2007 Volvo 780 with D16 engine 535HP 18 speed Ultrashift. I just bought this truck and the two harnesses were unplugged, when I plug them in, while driving I get a message (check engine coolant level at next stop) the message pops up and goes away but the coolant gauge reads normal. when I unplug the harness the message stop popping up and the truck runs normal with the coolant gauge still reading normal. Please any idea what that is?

 

It appears that the film is the tag with part numbers but have been painted over, I tried to remove the paint but won't com off without tearing and damaging the tag, when I get to a place where I can find a paint remover I will try to remove the paint to see if I find the part number. Here is another picture of the other side taken from the engine side.

 

Pablo,
I found out what that setup is, it's called Control unit, mounted with a sensor and a solenoid all on one plate as part of the active pressure system for some of the D16 engines. See the part numbers below.
Control unit PN# 21099272
Sensor PN# 3199259
Solenoid PN# 20753844

 

Dealer is really not helpful. Someone told me that VOLVO discontinue using this control unit on their trucks and they came up with a harness which bypasses the control unit but the dealer at Indianapolis couldn't pull up the bypass harness, does any knows what the part number might be to byipass the control unit in the picture above? Thanks for any information!