Underhood Lighting - Placement and Grounding

[DallasCajun]

I purchased a Underhood LED Light Kit that automatically turns on when the hood is opened. The question I have is where might be the best place to install it as the switch needs to be attached to a ground point. Any inputs or feedback would be appreciated.

From what I can tell there are 3 basic options:

1. Existing hole against the firewall: this is the most straightforward location but it sits so low that it would require some additional bracket to place it where the hood will make contact with the switch button. You can see that in the 1st picture below next to the 2 ground points. Not the worst solution to rig up some sort of bracket but then it's just that: jerry-rigged.
2. Drill a hole into the side flange of the quarterpanel. This is the easiest and most straightforward solution but I don't think the quarterpanel is a proper grounding point...if it's even metal to begin with. In the 2nd image below you can see the section I'm talking about. The 2 bolts circled in yellow connect through to the metal hood structure (and are ground points) but they are different bolt diameters and therefore won't work. The section circled in Orange is a consideration but I'm not sure that it can be used as a ground point. Any thoughts on this location?
3. Upper Firewall: The last place is pretty obvious, just drill a hole in the upper firewall, which is a ground point. The biggest challenge here is simply having enough space to get a drill in that space.

1st Option: Existing Hole in Firewall

2nd Option: Quarterpanel Section

3: Drill a Hole in the Firewall

 

[TurboS]

I would make a small bracket that attaches to one of the existing bolts in this drivers side front area with a short ground wire running to the chassis ground (negative battery cable attachment point) directly below the trail sight guide. The location will partly be determined to where the hood has a flat perpendicular area to depress the switch. Maybe off the aluminum corner brace bolt or in that area? My Superduty has a switch mounted in this area near the black hood bumper.

 

[Johnny Mo]

I'll be doing similar with one or 2 KC Cyclone lights - I think 1 is plenty based on the rock lights I just installed. I plan on using a magnetic reed switch instead of a ground pin switch. The switch I got is normally open and then when the contact is broken (hood open) it closes the circuit and lights the lamp.

 

[bmsehlke]

I installed a similar setup a few months ago. I chose the right side quarter panel for the switch and found out upon drilling that the painted material is composite and not metal (drills very easily) but you’ll have to ground to a ground point on the side wall. I can get some pics added in the next day or so if you want to see for reference.

 

[DallasCajun]

Thanks for the suggestions. I ended up taking a bracket out of my bin of odds/ends and adapting it for this purpose with a step bit to make the holes large enough for the switch and the ground bolt. I used the grounding point near the front of the bay next to the battery as it provided the best location for reliable switch activation. This did cause an issue with the length of the wiring but that's easily solved.

The 14" LED Strip was just a few inches too long to be properly positioned in the flat section under the hood so I snipped it and then sealed with some electrical tape. After testing functionality I mounted the strip and ran the wiring along the edge of the hood under the padding. In order to get the wire to extend to the battery mount I had to add about 12" of additional wire. For now I'm OK with it but will probably go back and cover it with some wire loon tubing and extend the ground wire enough to tie wrap it at the edge of the hood near the hinge, making sure to leave enough slack so it doesn't get caught.

In the end it does provide some decent light down into the engine bay; enough to not need to deal with holding a flashlight pointed in the right direction. If I really had to dig deep then additionally lighting might be needed but this will solve 90% of my needs when working under the hood.

 

[TurboS]

Thanks for the suggestions. I ended up taking a bracket out of my bin of odds/ends and adapting it for this purpose with a step bit to make the holes large enough for the switch and the ground bolt. I used the grounding point near the front of the bay next to the battery as it provided the best location for reliable switch activation. This did cause an issue with the length of the wiring but that's easily solved.

View attachment 11044
View attachment 11045

The 14" LED Strip was just a few inches too long to be properly positioned in the flat section under the hood so I snipped it and then sealed with some electrical tape. After testing functionality I mounted the strip and ran the wiring along the edge of the hood under the padding. In order to get the wire to extend to the battery mount I had to add about 12" of additional wire. For now I'm OK with it but will probably go back and cover it with some wire loon tubing and extend the ground wire enough to tie wrap it at the edge of the hood near the hinge, making sure to leave enough slack so it doesn't get caught.

View attachment 11049

View attachment 11050

View attachment 11051

View attachment 11052

In the end it does provide some decent light down into the engine bay; enough to not need to deal with holding a flashlight pointed in the right direction. If I really had to dig deep then additionally lighting might be needed but this will solve 90% of my needs when working under the hood.

Very Nice job on the install! Appears to provide considerably more light than any OEM under hood "night light", like you said, enough to actually do routine maintenance. If you should ever decide to change any part of this install you can now remove it without a trace since you didn't make any permanent modifications. It's all Good.

 

[Jhruzek]

Is that the kit from F150LEDS?

 

[DallasCajun]

Amazon - the link is in the original post.

 

[Jhruzek]

My apologies. I saw the red lettering, but didn't realize it was a hyperlink. This is definitely cheaper than the one at F150LEDs.