The other day my pump read no deliverly as a result of summer heat. After refilling a new reservoir I almost disposed of the defective one. Instead, I stored it in the frig and reused it three days later. Viola! It worked fine. I suggest this method for clogged reservoirs as a result of heat, not clogged from kinks in cannulas. Usually blood backs up in kinked cannulas and contaminates tubing and reservoir.

Poking a needle into the washer nozzle, wiggling it around, then spraying, then repeating several times, has always worked for me in the past.

Failing that, you might disconnect the hose from the nozzle and try blowing compressed air. If you suspect debris in the tank, try flushing it with a garden hose (making sure the water is gone before winter), or vacuuming it dry with a siphon pump.

I would avoid Draino. Anything that can burn human skin is probably not good for rubber hoses and electric pumps either.

You will likely find that the filter in the washer pump is blocked, you will need to remove it to clean it out, the motor is mounted under the right hand front wing/fender under the plastic shield