If you take the hose off the tank and it is clear through to the
nozzles (you can hook up the garden hose and squirt through to the
windshield) that certainly narrows it down...

 Take a close look at the tank, many pumps clip on the outside and
they push the inlet port through a rubber grommet into the tank - the
hard part is finding the exact replacement pump that fits on the tank.
The dealer parts counter can probably get you just the pump, instead
of a whole new reservoir and a pump together.

 (If the car was another five years older I'd say get both, because
the reservoir bottle plastic will get brittle with age.  Try replacing
the pump and the bottle breaks when you put pressure on it.)

 If that's too much money, and you can still suck the solvent through
the old pump, you mount an external aftermarket pump in line,
disconnect the power from the old pump and tap the new one in with a
couple of male-tab crimp lugs plugged into the factory socket, and
abandon the old pump in place.

Do not cut the wires on the car wiring harness!  You might find an
exact replacement pump in your wanderings, and you'll need the
connector again to hook it up.

     --<< Bruce >>--