I also just finished a mod I started a couple days ago. Since I shaved the holes for the windshield washers off my hood, I was looking for a new way to mount them. I noticed my Camaro has them mounted to the cowl cover, so I decided to try that. My old washers were in bad shape and I lost one, so I ordered some washers intended for the 2005+ Tacomas. I read on Tacomaworld that those have a better spray pattern and that was attractive vs just buying the older style ones with the dual streams.
Here are the ones I bought
20211101_200215 by
Jose, on Flickr
I had to design and 3D print some adapters in order to mount them to the cowl (the adapters fit pressed into the cowl and are then held in with ABS cement).
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Jose, on Flickr
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Jose, on Flickr
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Jose, on Flickr
I connected the two sprayers to each other using 5/32" washer tubing from Prestone (sold in a 6 foot length at Autozone) and placed a T-fitting in the middle of the tubing. This, in turn, connects to the tubing coming off the pump on the washer reservoir. The reason for the T in the center is to ensure even flow to both sides. I added a zip tie to each connection in order to avoid loosening over time (the T didn't feel all that tight on the tubing).
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Jose, on Flickr
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Jose, on Flickr
I used a single strand copper cable to fish the tubing from the pump through the fender well and out the cowl area so that I could connect it to the T-fitting. There is a readily available opening next to the reservoir through which you can put the tubing into the fender well.
20211110_184459 by
Jose, on Flickr
From there, you can run the wire up the fender well into an opening that leads into the cowl area. I tested the wipers to ensure the tubing wouldn't become impinged on the wiper arms and it all looks good.
Here they are with the cowl mounted to the truck
20211110_173844 by
Jose, on Flickr
A test showed that they were spraying properly, such that the windshield ended up evenly wet with the movement of the wipers.
20211110_184329 by
Jose, on Flickr