For some reason in the past, I came across this part number for a Sentra Intermittent Wiper Relay part number: 28510-1M200

It appears as though it might still be available. 

This is the wiring diagram from the EL section of the Sentra FSM:

Note that it is 7 wires. Edit: Oops, I finally noticed that there is no pin #4. That fits an observation that I made after I posted this. I'll have to see if this is a fatal flaw in my effort. 

Here is pin out on the 73 Intermittent Relay:

It seems pretty close to the same. I just have to trace out the wires better for the 73.

Edited September 28, 20222 yr by SteveJ
Discovered a possible mistake.

I think I'm making headway.

Here's a breakout of the 73 wiper wiring from the FSM. The problem is that it shows 9 wires whereas reality has 7 wires. This comes from the wiring diagram showing redundant connections for power and ground.

Now that leaves other issues that I need to resolve:

1. Is the YG wire I identified in my first post the power wire? If so, why is it coming from the engine harness? Is it connected to the wiper motor fuse?
2. Would the wiper motor work on the washer push button without the blue wire connected? In the 73 relay, it's a power source. It appears as though it may not be needed for the Sentra relay. 

I guess it's about time to break out my meter.