When I turn my wipers or washer fluid sprayer on, the engine drops RPM?

This is due to one of two issues. Either your washer/wiper motor is drawing way too much current and dragging the alternator down or the alternator is failing and not able to keep up with the load.

So, this means we need to start with load testing the alternator so that we can make sure this is ok.

Here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

https://www.2carpros.com/articles/how-to-replace-an-alternator

If this is okay, then we need to check the current draw on the wiper motor. You can do this with an amp clamp to find out if this is the issue but normally this would blow a fuse if it is drawing this much current.

So, let's start with the alternator and go from there.

Let me know what questions you have, and we can go from there.

Thanks