How to Upgrade Your Vehicle's Exterior Incandescent Bulb to LED




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Tutorial on how to upgrade your vehicles factory exterior incandescent bulbs to LED. For this I am working with a 1998 Ford Ranger, upgrade procedures will vary between vehicles, but for the most part it's quite straight forwards. This write-up will include upgrading your signal lights, reverse lights, and brake lights. LED lights not only look great, but they have a higher light output, can increase visibility for you, increase your road presence, faster start up and shut down time, longer life, and reduces load on your electrical system.

Tools/Supplies Needed:

  • screwdrivers
  • socket set
  • relay
  • cable ties
  • new replacement LED bulb

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Step 1: Signal Lights

Starting with the front of the truck, for the Ranger there will be two small 1/4” bolts which holds on the front signal lights. Next, there is a plastic shroud which needs to be pushed down and the parking light assembly can be pulled out. Each of the light sockets, there are three in total must be twisted counter clockwise in order to disconnect, then pull out to remove.

The bottom signal light does take two bulbs which is bulb model number 3157, so you will need 4 in total for the replacement. These bulbs simply pull out of the socket.

When installing the new LED replacements, ensure they are in the correct orientation by turning the parking lights or signal lights on and test. If the bulb does not work, flip it around as you are reversing the polarity and LEDs will only work one way. Remove the other bulb and replace. Reinstall the lights back into the housing and then the housing can be pushed back into it’s location. The plastic shroud will need to be pushed down as it goes over top of the lights frame, then reinstall the fasteners. Move onto the other side for the same process.

With the rear, the top bulb in the tail light housing needs to be replaced. There will be 4 phillips screws which needs to be removed. 2 on the inside edge where the tail gate is and then 2 on the outside of the tail light assembly. If you plan on upgrading the brake and reverse lights also, it would be best to leave the tail light out and follow the steps in the next procedures.

After those screws have been removed, the tail light can be pulled out of it’s location. To remove the bulb socket, the electrical connector must be removed first. The socket cannot be twisted as there isn’t enough clearance for the connector. In order to remove it, spread the clip tabs and pull back. Now twist the light socket counter clockwise and then pull out. Pull the bulb from the socket.

Install the LED replacement, the bulb number is 3156 which is a single filament style bulb. Again, ensure the bulb is in the correct orientation. Reinstall the tail light, then do the same for the other side as well.

Next we must remove the hyper flash issue which LEDs can cause due to the large load drop on the vehicle’s signal circuit. Hyper flash is when the light flashes excessively quick. This truck uses a mechanical relay and that needs to be changed to an EP27 relay. Not all vehicles can have their relays replaced as the signal operation is controlled by a computer rather than mechanical electronics. For this truck, the relay is located under the dashboard on the driver’s side. It is a yellow relay and can be accessed without removing any trim panels. If you are unsure about which relay your vehicle uses for a flasher, refer to your owner’s manual, a vehicle specific repair manual, or activate the signal lights and follow the clicking sound, then touch the relay to feel the pulse. Plug in the new relay and considering the retaining clip was part of the old relay’s case, I used a cable tie to hold it into place. Test the lights to ensure everything is working correctly.

Step 2: Reverse Lights

Some tail lights will have an access hatch from the back, unlike this truck which is required to have the tail light assembly removed. In order to remove it, follow the steps in the signal light upgrade section. This tail light removal procedure is quite common amongst most of the Ford Ranger models, 1993 and up. Before removing the bulb, considering this is a truck it’s good to clean off any loose debris on the rear of the assembly so nothing falls inside the light housing. To remove the bulb socket, grab firmly onto the back of the plug, then rotate counter clockwise until it stops. Pull straight out and to remove the bulb from the socket, simply pull straight out. You will need to match your existing bulb to an LED upgrade replacement, they are based off the same model numbers. For installation, push the new LED bulb into the socket and then test to ensure it works. To check, make sure my wheels were blocked, apply the emergency brake, turn the vehicle to the on position but there is no need to start it, and then select the reverse gear. Reinstall the bulb and then move onto the opposite side.

Step 3: Brake and Rear Parking Lights

The tail light removal procedure is the same process as what was listed in the signal light upgrade. Remove the bulb and socket by twisting it counter clockwise and then pulling the socket straight out of the light assembly. Remove the old bulb and install the new LED bulb and you will need to ensure it’s orientation is correct so you basically have a 50/50 chance on this. Test the bulb by turning on the parking lights or activating the brake lights, if it doesn’t work, then turn the bulb around. Install the light socket back into the tail light housing. Install the tail light back into the truck and reinstall all the screws, then tighten.

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    8 Discussions


    1 year ago

    Would just like to point out that putting LED brake light bulbs instead of the normal bulbs will disable your cruise control unit

    Looking through briefly, nothing looks amiss *technically*, however, if you are in the U.S. you are most likely breaking the law by upgrading your stock lights without putting them in a vehicle-specific housing assembly. stock headlights are designed to use a specific type of bulb to ensure they meet maximum brightness standards, as well as correct projection angles. by slapping a different bulb in the original housing, you are very likely changing the characteristics to make them unsafe and not road-legal. HID and LED headlights are a huge problem where I live, because we don't have much streetside lighting, and people install brighter lights to compensate, causing them to appear ultrabright compared to the road for oncoming drivers. combine this with an aftermarket lift on a truck (also common here) and you create a pretty potent road blinding machine.

    Please research applicable headlight laws regarding your specific vehicle before installing aftermarket headlight kits. just because the kit is "street legal" doesn't mean it's legal in any vehicle as installed.

    6 replies
    TCSC47brad ley

    Reply 1 year ago

    It is correct that your Instructable only refers to side lights, but ICBM's warning is very apt. Your article should have contained his warning as it goes a long way towards encouraging swapping main headlight bulbs for perhaps inappropriate LEDs even if it does not show it.


    Reply 1 year ago

    As mentioned above I will be producing a headlight specific LED upgrade eventually, covering all those areas.

    This tutorial does NOT contain headlight bulb upgrades which would be halogen. Technically halogen bulbs are an incandescent as well, but I didn't consider it as the traditional style. I most likely will product a specific headlight upgrade as well in the future. I have been experimenting with a couple different vehicles and am aware of the laws and possible difference in light output. All will be thoroughly tested anyway with physical proof.

    I'll admit I jumped the gun here. I saw this promoted and didn't check that it was actually headlights before posting that comment, I just saw the lights and skimmed to see if you mentioned the legality. I apologize for the accusation.

    on that note though, I do urge you to make mention of the laws in this and any instructables regarding replacing vehicle lights, because exactly as TCSC47 said, this goes a long way to encouraging people to replace vehicle bulbs.