How to: Install LED Under Hood Lighting

gamefreakgc

Elite Member
I wanted to share how I installed a simple, inexpensive LED hood lighting system. I recently installed mine and wondered immediately why I did not do this sooner! No more awkwardly holding flashlights on repairs, or fumbling around in the dark when I'm trying to get to something in the engine bay.

Here's the finished product:

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The LED lights are very bright, they put out about 600 lumens pointed directly on to the engine bay. There's lots of colors to choose from as well if you want to get fancy. My total cost was $33. Interested? Here's how you can do it yourself!

Part order list from Superbrightleds.com and Amazon:
Optional items:
  • 3M Adhesive wire clips - For attaching wire to hood/frame. Alternatively, you can thread the power wire through the hood itself and use zip ties.
  • LED interconnect clips - If you want to cut the LED strip into multiple lengths you'll want these to connect them together.

Tools and supplies needed:
  • Drill with 5/16 drill bit
  • Wire stripper
  • Wire crimper or pliers
  • Rubbing Alchohol
  • Rag
  • Electrical Tape
  • Zip ties
  • 13mm or 1/2" wrench or pliers

Step 1 - First you want to decide how you want to arrange your LED lights. On the light strip, you'll see a cut indicator every 3 LEDs. Simple cut along it and use the interconnecting wires to string it together. I went with a 3 strip configuration seen below. Be sure to keep polarity the same, meaning all the "+" sides of the strip on one wire and all the "-" sides of the strip on the other wire. The extra wiring on the far side of the LED can be cut off and used to extend the power wire.

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Cut off one end of the LED wiring connector and plug it into the other size, doubling the length of the protected wire, with bare wire leads on the end. Strip off the leads so you have some extra bare wire and attach the 18 AWG power wire to each lead. The LED carries a very small current, simply stripping about 1/2" on each end and wrapping one end around the other end is sufficient. Protect each wire end by wrapping with electrical tape to ensure they do not pull apart.

If you did decide to cut the LED strip, test the leads on the battery by taking the power wire and touching the black wire to the ground terminal of the battery and the red wire to the power terminal of the battery. You might need to strip off a little bit of the wire to do this. If any sections of the LED do not light up you switched up the polarity and you have a "+" end connected to a "-". Disconnect and correct so all are in line and it will light up.

Step 2 - Now you want to prepare the surface for mounting. Clean the area of the hood that's directly behind the rubber gasket. You can see where the LED's will be mounted here:

gamefreakgc-albums-interior-body+mods-picture50329-img-2386.jpg


If you are using the 3M adhesive wire clamps, also clean the driver's side of the hood on the inside of the bulge. This is where you will run your wiring. The surface should be very clean, your finger should squeak as it runs along the surface.

Apply the 3M Adhesive Promoter. Since this is being installed in a hot engine bay you do not want the LED strip or the wire clips to warm and fall off into your motor. The package says it must be applied between 60*-80* weather. It was 50* here and it worked fine so just make sure it's not freezing or insanely hot out when applying. On the clean surface, take the applicator sponge and wipe down the surface the LED lights will adhere to. Do a test fit holding it up to the hood to see what areas will need it if you are not sure how big of an area to apply it to. Use it where you will put the 3M wire clips as well.

Step 4 - Attach the LED strip light by removing the backing and placing it in the crease shown in the photo above, making sure the 3M Adhesive Promoter is dry. With the hood open, you want the LED's shining down and slightly inwards towards the cabin, you do not want them shining back out the front of the vehicle and blinding you. Most 5050 LEDs have about 150 degree light disbursement so you have room for error here. Once you've placed the LED, attach the power wire to the 3M clips where needed to secure the power wire down the driver's side all the way down to the hood hinge. Take your time and plan it out. I only ended up using 4 clips. Alternatively, you can pass the wire through the holes in the bulged section of the hood and thread it through with a coat hanger or similar object and not need to use wire clips.

When you get to the hinge, make sure you route the power wire on the top half of the hinge only, since the lower hinge will act as a scissor if any wire gets in the way. I tucked the wire under the trim piece as shown below:

gamefreakgc-albums-interior-body+mods-picture50328-img-2385.jpg


Thread the wire past any accessories and up to the area behind the driver's headlight, securing with zip ties as needed.

Step 5 - You will now need to drill a hole into the frame for the pinswitch, which controls your ground wire. Locate the area just to the side of the driver's side rubber hood stop where it is flat. You'll notice on the hood there's a smooth, square patch that sits over this spot of the frame, this is what we want striking the switch. You want to put the hole on a perfectly flat part of the frame for ease of install.

gamefreakgc-albums-interior-body+mods-picture50327-img-2384.jpg


Drill a hole using the 5/16" drill bit but be careful, there is a wire harness right below. You can unclip the harness and pull it out of the way if needed. You can see in my photo the switch is a bit crooked, it works fine though but my drill bit slipped and the hole was on an uneven part of the frame causing it to lean to one side.

Next take off the lower nut and washer off the pinswitch and thread the switch through the hole. Slide the washer and then the nut on the bottom and secure it with a 13mm wrench or pliers until snug. The top of the switch should be higher than the rubber bump stop to ensure when the hood closes it presses on the switch. It does not however need to press down completely to work, only enough to press the male spade off the threading at the bottom.

Step 6 - Complete the wiring by taking your power wire and crimp the supplied female spade on the wire using a wire crimper or pliers and attach it onto the bottom of the pinswitch.

For the power wire, you will need to find a power source coming from the fuse block or if your engine bay looks anything like mine, simply tap a fused power source. I used my light bar wiring since the hood LEDs take very little amps. Simply crimp the T-tap onto the fused power wire, attached the male spade onto the 18 AWG power wire from the LEDs and insert the spade into the end of the T-tap securely. If you do not have a fused power wire, you can tap a fuse in the fuse block using a fuse tap or fuse doubler. It's best to tap a fuse that does not control any major engine functions to ensure that if a fuse does blow, you are not left stranded.

Once you hook up the power wire to your source your lights will come on:

gamefreakgc-albums-interior-body+mods-picture50330-img-2389.jpg


Close the hood securely and look under the vehicle to make sure they are off when closed. You can also peek through the crack between the hood and the frame to ensure the pinswitch is being pressed down correctly. If not, loosen and adjust.

Enjoy your new LED lighting and no longer having to work in the dark!

gamefreakgc-albums-interior-body+mods-picture50326-img-2380.jpg


P.S. in the photo above on the right of the hood you can see the complete wiring path I used to secure my power wire.
 
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Hell yeah! The lights alongside the hood struts make it look very nice and sleek.

I might be beneficial to add LED strips on the lower inner fender panels also, for under/side engine work. Might need a better mount than the adhesive for that though, due to dirt and rain, etc.
 
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Hell yeah! The lights alongside the hood struts make it look very nice and sleek.

I might be beneficial to add LED strips on the lower inner fender panels also, for under/side engine work. Might need a better mount than the adhesive for that though, due to dirt and rain, etc.

Totally, now that I have the switched ground and fused power I can easily wire up any assortment of lighting from the hood!

They also sell a waterproof LED strip: https://www.superbrightleds.com/mor...-with-18-smds-per-ft-3-chip-smd-led-5050/936/

I almost got this one instead but it's a little bit dimmer so went with the brighter strip. Both are rated for vehicle use and are water resistant, that one is completely waterproof though so I could put it anywhere!
 
Well done! I would highly encourage anyone thinking of doing this to follow through. My underhood lighting is so nice to have, even for simple stuff like oil changes in the garage.
 
This is cool, I've looked into doing this before, but always forget about it. Thanks for the write up!

I need to order a few other bulbs from them sometime so I'll throw this stuff into the order too.
 
Most of my vehicles have one of these GM underhood light reels installed in them. The reel is probably 20-25 feet and the light has a magnet on it to stick it anywhere you need light. Crank the handle by hand to pull the light back to the housing. These lights are found under many late 80s to mid 90s GMC/Chevy pickups. Two screws and be sure to get a short section of the wiring harness including the plug.
002-gm-reel-underhood-led-lamp-unit.jpg


A link to an article the stock photo came from: LED Revival of a GM Underhood Reel Light

Also have one from an early 80s Ford pickup that's self retracting (like a shop mounted cord reel), but it has gotten to the point where it doesn't want to retract the last foot or so of wire.
dfs.jpg
 
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This is a great idea, I'll definitely plan on implementing at some point.

One thought/suggestion - in addition to the pinswitch, I'd use a manual on/off switch. I'm thinking that I will not want all the LED's to kick on every time I open the hood, or if I am working on the motor for hours on end on a bright day - no need to have all the LEDs on. But having the pinswitch in addition to the manual switch is probably good too, in case I forget to turn off the manual switch before closing the hood.

So basically two switches in series, pinswitch and manual switch.
 
This is a great idea, I'll definitely plan on implementing at some point.

One thought/suggestion - in addition to the pinswitch, I'd use a manual on/off switch. I'm thinking that I will not want all the LED's to kick on every time I open the hood, or if I am working on the motor for hours on end on a bright day - no need to have all the LEDs on. But having the pinswitch in addition to the manual switch is probably good too, in case I forget to turn off the manual switch before closing the hood.

So basically two switches in series, pinswitch and manual switch.

I almost wired in a simple toggle switch myself, since the LEDs draw very little amps you can put it straight in the ground wire, no need for a relay. I might add it eventually if I find that I need it, I can also just pull the spade out of the t-tap easy enough as well. You definitely want the pinswitch though, if you forget about it you'll wake up to a dead battery!
 
Nice mod & write up! I planned on doing this down the road. For now I use a magnetic & hooked LED flashlight.
 
Well done and a great idea. I should definitely add it to my to-do list. I recently changed my car lights, and it wasn't as easy. I hoped it would be easier, but I managed to put everything together, and it works fine so far. This one should be easier, especially taking into account that I have your post as a reference and could use it to see if I can do the same for my car. I never thought about LED strip lights under the hood, but now when I think about it, it's actually a great idea. Makes things easier when you have to work on it during the night.
 
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4 years later and I still am glad I did this. Makes late night repairs or engine checks much easier plus you can make it fun and use colored LEDs for show.

Always fun to see people still finding your really old posts and bringing them back to life, right? ha ha

Definitely a great DIY. That's going on my list just like many others who saw this :thumb:
 
I wonder how far LEDs have come in 4 years.

I have the pins to do this; might just bite the bullet and order everything else.


Sent from my iPhone using Tapatalk
 
Underhood LEDs are very useful. I did this a year or 2 ago and ended up eliminating the pin switch in favor of another ground location and an under-hood push-button switch. My pin switch was coming loose and causing grounding issues and I wanted a more basic on/off action. Can't go wrong with a well-lit engine bay!
 
I did this 6 months ago after reading this post. I used a pin switch like Jerod but also added a 2-way switch. Opening my hood at the gas station at night to check my oil was awesome, like magic with the Spiker Engineering hood struts. I got rid of the pin switch last month after the pin developed a light coating of rust and stopped working. The 2-way works great and is all I really need but one of these days I'll coat another pin switch with something and reinstall.
 

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