What is this part?

[Delboy]

Hi,

I was told I might need this part replacing on my car, yet have no idea what it is called.
Under the plastic engine cover(the one with the 3 star stamp), is a part on the left hand side with tubes going in and out of it. It is attached to the engine with torx bolts. On the front of it are some markings, with + and - signs. It's smaller than an iPhone.

Any help is much appreciated, thanks.

[Delboy]

I figured it out, it's the change over/switch over/diverter valve.

thanks