Where is the wiper relay
A wiring diagram doesn't show a relay, just a 25 amp fuse in fuse panel under driver's side of dash. Intermittent working is usually from a loose or poor or corroded connection, or the switch is old and tired, or the motor is old and tired. Here is one way to check, if you have a test light: when the wipers are not working with wiper switch on high, and key is on, pull off the connector to the wiper/washer motor module (in the engine bay, on the firewall) and check if the purple wire has power. If it does, you probably need to replace the module. Inside the module is a park relay switch (to return wipers to down position when turned off) and a circuit breaker between the motor and ground.If the purple wire does not have power when key is on and wipers on high, the connection is lost between the switch and the module, or the switch may be malfunctioning. The switch has 5 wires, white wire from 25 amp fuse (power in to switch), a pink wire (for the washer motor), a purple wire (high speed wipers), a dark green wire (low speed wipers), and a gray wire (for the park relay switch inside the wiper/washer motor module). If you see a yellow wire also at the module, that is part of the low speed wiper circuit (the dark green wire) coming from the park relay switch and then to the motor.Good luck. Post back if further questions, or need more help.