I recently asked about some open space in the engine bay, directly over the left front wheel. Thanks to all who answered, That knowledge went into this project.
https://wranglertjforum.com/threads/what-goes-here-and-what-size-bolts-did-it-use.57954/
Another recent post was how I replaced a harness wiring connector as it was part of another project to add an under hood reel light. In that thread I went into the detail of how to crimp and install terminals, so I'll skip those steps in this thread.
https://wranglertjforum.com/threads/replacing-wiring-connector.58013/
Here's my version of mounting one of these under hood lights:
It all started with a template.
Once I had the template cut out, I did a test with the mounting points I planned to use.
I started with a 6-inch square piece of 1/8-inch thick 6061 aluminum, trimmed it with a jigsaw, drilled all my holes, and sanded it smooth. This ended up being the test mounting plate.
I made a jumper that would connect the GM light to the Jeep's harness connection. I checked which pin in the reel light corresponded to the base of the lamp. While a filament bulb doesn't care if the base is positive or not, some LEDs require the positive lead to be there, so I had to reverse the wire order. Top and middle are the original harness, the bottom is my new connection.
Test mounting plate, light, and harness in place.
While everything was able to mount up fine, a couple of my holes were drilled slightly off-center, so I decided to take another swing at the mount.
My template's two holes that correspond to the fender mounting bracket under the fender were spot on, so I drilled those, mounted the new plate and marked the third hole from the underside.
Marking the third hole.
Third hole mark.
Once that was drilled, I remounted the plate and oriented the light how I wanted. As I placed the light and marked its mounting holes I kept a socket on the closest bolt so I know one would fit on the bolt's head if I ever needed to tighten it.
Once marked, I center punched and then drilled the light's mounting holes. I didn't have a center punch when I worked on the first mount and learned from that mistake. I bought one last night and today every hole was right where I wanted.
I sanded the mount on both sides then fed one bolt for the light up from underneath and the mount was bolted in. The fender drops down where that particular light mounting bolt comes up, but the bolt is longer than the drop, so it is somewhat captured. An open-ended wrench fits under there to be able to tighten things. I didn't drill a fourth hole for mounting the plate. I found the three on the test plate to be sufficient.
Once the light was mounted I did the connection that would plug the new jumper into vehicle's harness connection.
Jeep and GM ends of the jumper.
I ran the jumper along the top of the bay. Once everything was in place it was all zip-tied.
I capped off the stock under hood light with a spare connector to keep it somewhat weatherproofed.
I used an LED that has a frosted globe on its top because it fit under the light's globe. How does it look? When you switch it on in place it is decent, but that's not where it'll get the most use.
Where it really works is when you mount it on the hood, just behind the hood release, using its magnetic base.
Awesome light and I'm glad this thread got me going down this path. Thanks all!
Also, I have my test plate and a spare 5-foot jumper cable if anyone wants them for their own light project. They both work, I made two plates and cables in case I bungled one. The test plate is marked with where I was going to cut it, but I went ahead with making the second one and never got to trimming it. It fits as-is, but that's why its marked up.