They come on every 6th time with your windshield wipers.
The pump is the one that is closer to the front end of the car at the washer bottle.
Easy way to test if its the pump. Have someone activate the washer and listen if you can hear the pump running. If the pump doesn't run its dead, if you can hear the pump what might of happened is the actual gear inside has failed not providing enough pressure to pop the headlight washers out.
I just had mine replaced earlier this year. I even managed to find a pump on ebay for $12 compared to what everyone else charges for these of $40+..
Ill find the link to my old post where it had a bunch of troubleshooting steps.