DIY Project 61

Automatic Underhood Lighting

by Blazein800

There was a time all cars came with under the hood lighting either automatic or at the flip of a switch. Well now very few cars do and if you ever have to pop the hood at night to check fluids or just to show your friends how nice and clean your Elantra's engine is you need some type of exterior lighting. Well here's a very easy DIY that will make looking under the hood at night a lot easier or just add some colored lights to jazz up your engine.

Parts Needed:

1. Aftermarket lights or LED's (I used LED's from Autozone that are red and came in a pack of three and I also used triple LED dome and utility lights from autolumination).

2. Electrical Tape

3. Large Yellow Eyelet (1)

4. Blue Female Electrical Connector (1)

5. Inline fuse

6. Pressure Switch

7. Blue Tube Type Wire Connectors (4)

8. Enough electrical wire to run from the lights to the battery (power) and from the lights to the pressure switch (ground). I used approximately 12 ft. of 20 gauge wire.

9. Grounding Washer

Note: All of these components can be purchased from an autoparts store or Radio Shack.

Tools Needed

Metric Wrenches
Drill and Bits
Wire Crimpers

The Project:

Step 1. Disconnect the negative battery cable.

Step 2. Decide where you want to mount the light. I mounted mine through the hood felt using a small screw driver to poke the holes in.

Step 3. Decide the best place to put the pressure switch in. The switch I used was a typical Pen switch that makes ground contact when released. I mounted mine through the far right screw hole that is used to secure the battery cover.

Step 4. Measure wire needed and include the Inline fuse in the measurement to insure you have enough wire. NOTE: Hate to stop half way through the job and have to take the wife's car to buy more wire.(You'll never hear the end of it!!)

Step 5. Mount the light allowing for easy access to its wires so you can add more wire to it in later step making sure that it will be clear of any engine components when you shut the hood. NOTE: LED's are not as fragile as bulbs for when you shut the hood but are not as bright unless you use several in sequence.

Step 6. Mount the pressure switch making sure to mount it through metal using the grounding washer. Make sure there is good metal to metal contact between the car and the switch mounting spot. I had to remove the black plastic scew to the battery cover and drill a slightly bigger hole through the plastic. NOTE: Make sure there is enough room under the mounting area for the switch to be depressed downward.

Step 7. Using wire run the lights power wire through the inline fuse to the positive battery cable. Here is where you will use 3 blue tube type wire connectors to extended the light power line and add the inline fuse. Also the Large Yellow Eyelet to the Postive battery cable excessory nut. Where the main positive battery cable is attached to the battery. NOTE: I ran all my wire from the light to the battery and pressure switch along the inside of the left side fender well to hide the wire and to prevent it from getting damaged.

Step 8. Using the additional wire run the lights ground wire to the pressure switch. You will need to use the last Blue tube wire connector and Blue female wire connector here. Once the ground wire is connected to the pressure switch the light should come on. If not then the switch is not adjusted correctly or the switch itself is not grounded to the car. NOTE: If you can not get the switch to ground itself then run a seperate ground from the switch to the cars body or frame bolt. Do not run the lights ground wire directly to the frame or the light will not go out when the hood is shut.

Step 9. Next slowly lower the hood while looking at the light until the hood is almost completely shut to see if the light will shut off. If the light doesn't shut off then you will need to adjust the switch so that it makes contact with the hood sooner. NOTE: Do not raise the switch to its highest position for the first adjustment. Contact will be made very early but the switch will interfere with the hood closing which could cause you to dent the hood. It is best to use the lowest or lower position first.

Step 10. Replace negative battery cable and enjoy.

- Blazein800