Any idea what would cause only one side to work?

 

Could be a few things, check the wiper arm is secured on the spline (at the base of the wiper arm) If it is time to check the linkages

 

The wiper works fine. It's the washer that isn't working. Fluid comes out fine on the drivers side but no fluid from passenger side wiper.

 

Probably just clogged. Try cleaning the nozzle with a needle.

 

Doh!!! My bad, blockage or split / broken pipe.

Mixing screenwash can make it gunk up.

Check screenwash reservoir and flush pipes with pressure wateror ccompressed air

 

Thanks, I'll try that

 

As I recall there is a "T" fitting towards the passenger side windshield just under the cowl, carefully disconnect and start blowing there toward wipers.

 

I had this issue too, and for me the hose was disconnected at the base of the wiper arm inside the engine bay. If you spray wiper fluid and then check under the hood and see wetness near the firewall then your hose just needs to be reconnected.