Headlight washers.

[Marty-g]

Hi all, I wonder if anyone could shead some light on how these work as mine have packed up. I've had a look on parts base at the washer system but it doesn't really help. My question is, does it have its own pump to power it? When I wash the screen with the lights on I can hear the relay clicking after a few seconds which is when the headlight washers would give a squirt. That's what makes me think it's a separate pump. I'll give it a scan to check for any codes( if it throws one up), but other than that I'm at a loss as to what it could be. Any advice much appreciated, thanks in advance.