Technical Rear washer blocked

[Poperon]

Hi,

Rear washer problem. Barn door model.

Front washers work fine.

Rear ones, pump sounds when activated but no water from sprinkler.

Inspected sprinkler...clear. Sucked on the hose and blew down the hose....definitely blocked.

Any idea where these pipes are routed and where do they commonly get blocked?

Thanks

Ron