Under Dash Lighting




Introduction: Under Dash Lighting

Create a unique feel to the inside of your vehicle with these simple and inexpensive steps.

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Step 1: Gather Supplies

What you will need:

-Two or more LED light strips

-5-10ft of red and black 16-18 gauge automotive wiring

-Wire Strippers

-Soldering Iron(Optional)


-Black electrical tape

-10 amp inline fuse


-Zip Ties

Step 2: Find Fuse Box

Find the fuse box in your vehicle. This should be inside the car somewhere. In most vehicles it will be on or around the dash in some manner. Some common places to look are: on side of dash on drivers side with door open, on side of dash on passenger side with door open, inside glovebox, under dash near pedals, and on some imports such as BMW in the trunk near the battery could be a possibility.

Step 3: Choose When You Want Lights to Be On

The under dash lights can have different settings of when they are turned on. One way is to have them come on with the parking lights/headlights. The other way is to have them come on when the vehicle is started, and shut off when the vehicle shuts off. In either situation, the wiring is almost the same.

  • To come on with headlights:
    • The fuse for this can sometimes be a little tricky to locate. The goal is to find the fuse that already controls the interior lights of your car. This can be labeled many different things such as, Gauges, Interior Lamps, Dash, Lights, ect. Look for something that resembles these.
  • To come on with vehicle:
    • This method is more straightforward than the earlier one. Again there is more than one fuse that can be chosen for this method. One option is to put it on the same fuse as the radio, which means whenever the radio is on, the lights are on. Another option is to use the fuse for the ignition, which means whenever the key is turned on and the car is running, the lights will also be on.

When choosing either of these two methods, all that is required is to splice into the wire to that fuse. By using a multi-meter locate the hot side of the fuse. To do this, simply use the black probe of the meter to stick to a grounding part of the vehicle, and the red probe to the fuse. Place the red probe on one side of the fuse while it is still in the fusebox. If no voltage is detected, then test the other side. Whichever side does NOT have voltage is the side that you will splice into. NOTE: the key must be in the on position for this procedure. Locate the back side of the fuse box and the wire coming out of the side of the fuse, and splice your wire inline with this wire using a connector. The reason for putting it on the dead side of the fuse is to allow extra fire protection.

Step 4: Locate a Grounding Point

Locate a spot under the dash of the car that you can use for a ground. The ground is one of the more crucial steps in this process. The most likely place will be the firewall. The firewall will be located under the dash of the car, separating the engine bay from the inside of the vehicle. On the firewall there will be multiple spots where parts are bolted to it. By removing one of these bolts and using a connector to slide under the bolt, you can form the ground. Be sure to tighten the bolt back down securely.

Step 5: Add the Inline Fuse

For the red wire that you now have connected to the fuse, you need to add another inline fuse to this circuit for added safety. Connect the fuse inline as close as possible to where it is connected to the fusebox.

Step 6: Connect Wires to LED Strips

Connect the wire that you have connected to the fusebox and the wire connected as a ground to the first of two LED strips. While splicing this together add another set of wires to this connection to run to the second LED strip. Once this connection is tight run the wires over to the other side under the dash and connect the other strip.

Step 7: Test

Now would be a good time to test everything before you make the final adjustments . Depending on which way the lights are wired will alter the procedure of testing slightly. Turn them on in whatever fashion they were wired, if they do not light up there are some steps for troubleshooting at the end of these instructions.

Step 8: Mount LED Strips

At this point you should have decided where exactly to mount the LED strips. The most common place is on the plastic under the dash. NOTE: Be sure to account for where the wiring will go before this step! Be sure to route it so it can be hidden, and so it is out of the way of any moving parts such as the steering column and pedals. Remove the paper covering the adhesive and stick the strip to the surface. Be sure to hold it for at least 60 seconds to allow the adhesive ample time to set up and bond the the surface.

Step 9: Tidy Up Wiring

This is the time to tidy up all of the wiring going to the strips. Zip ties are a good tool to keep the wiring out of sight. A good way to do this is by tying the wires into the existing wiring harness in a vehicle. Most vehicles have a piece of the body wiring harness running through under the dash. If this is not available, any part of the dash will also work. Anything that will not allow the wires to get tangled into any moving parts will be fine.

Step 10: Troubleshooting

  • Lights will not turn on
    • Check Fuse
    • Check all connections for tightness
  • Only one light is working
    • Check connection to that strip
    • Check that LED strip is still good by hot wiring straight from battery

Step 11: Disclaimer

Aftermarket lights inside a vehicle are strictly prohibited in some states and counties within those states. Be sure to check with local law enforcement agencies before making any modifications to the inside of your vehicle.

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    8 Discussions


    3 years ago

    Another option for the fusebox connection is something called an 'Add-A-Circuit' or 'fuse adapter tap' They can be had on Ebay for about $1 delivered.

    It simply plugs into any of the fuse slots in the fusebox. It has two fuse slots. One for the original fuse, and one (with wire pigtail) for the LEDs to connect to.

    No cutting or splicing of original wires and can easily be removed. This is important if your car is under warranty, as cutting the original wiring could void the warranty.


    Reply 7 weeks ago

    Maybe you should make an instructable about how you did yours! lol


    Reply 1 year ago

    I'm trying to hook my under glow with my headlight so when I turn on my headlight they come on when I turn them off the underglow goes off how would I hook then up


    Reply 1 year ago

    This can be tricky, as modern headlights are controlled by the car electronics, CANBUS or whatever (for DRL & delayed off functions). You will just need to experiment with a meter & try to find a fuse that is only got 12volts when your lights are on. If you find one, plug the Add-a-Fuse into it.

    The OP actually covered this as well...

    To come on with headlights:
    • The fuse for this can sometimes be a little tricky to locate. The goal is to find the fuse that already controls the interior lights of your car. This can be labeled many different things such as, Gauges, Interior Lamps, Dash, Lights, ect. Look for something that resembles these.
    Honestly, I wouldn't bother with this route. There are cheap LED controllers that not only offer a keychain remote on/off, but offer strobe, pulse, flash, etc functions for the LEDs. For even more $$$ there are cell phone controlled ones.

    I found some unused, empty fuse slots (for options I didn't have) in my cars fuse box. That's where I source power for LEDs, airhorn, etc. Just have to experiment with a meter.

    4 years ago

    I tired wiring the hot wire (red) to the battery then using the inline fuser straight to the led light. Given that I grounded the black wire and the led flickered but didn't fully light up. could you give me some advice?? thx.


    Reply 5 months ago

    The LEDs will only light if they are wired correctly. The positive wire should be red and the negative should be black. If they are different colors try reversing them. It won't hurt the LEDs, they just won't light if the power leads are reversed


    5 months ago on Introduction

    A ten amp fuse is too high, you can find fuses that are 2.5 amps and less depending on the style of fuse. It is better to fuse about twice the current draw than ten times it.


    5 years ago on Introduction

    This looks like a great idea!

    Did you happen to take any photos of the process that goes into installing these lights? If you added some photos to the steps, I think a lot of people would really find this useful. Just a thought! :)