Headlight flashers, also known as wig-wags, are used by police, medical and fire personnel to make their vehicles more visible while responding to emergencies. The flasher is triggered by a switch in the passenger compartment and causes the vehicle's headlights to alternately flash between high and low beam. When activated, the headlights flash in a distinctive pattern that is very noticeable, even at long distances. Installing the flasher module is not difficult and requires only basic tools.
Things You'll Need
- Open-end wrench
- 3/8-inch drill bit
- 3/8-inch grommet
- Circuit tester
- Wire strippers
- Wire nuts
- Ring connector
- Wire crimper
Mount the headlight flasher control box in a location that is easily accessible from the driver's seat. Use the included screws to fasten the control box to the dashboard, kickplate or console.
Choose a location on the vehicle's firewall to run the wiring harness from the control box through. Check both sides of the firewall to make sure there is nothing in the way that could be damaged by drilling. Drill a 3/8-inch hole in the firewall in the chosen location. Insert a 3/8-inch grommet in the hole.
Feed the wires from the control box through the hole in the firewall. Run the fused red wire to the vehicle's battery. Run the brown and white wires to the driver's side headlight. Run the green and yellow wires to the passenger's side headlight.
Turn on the headlights and switch on the high beams. Test the headlight wires with a circuit tester to find the wires carrying voltage to the high beams. Mark the wires with a piece of tape. Turn off the headlights. Use an open-end wrench to disconnect the negative battery terminal.
Cut the marked wires 18 inches behind the headlights. Strip 1/2 inch of insulation off the ends of the cut wires. Slide the stripped end of the white wire from the control box and the stripped end of the wire attached to the driver's side headlight into a wire nut. Turn the wire nut clockwise until it is firmly attached to the wires. Slide the stripped end of the brown wire from the control box and the stripped end of the wire that is no longer connected to the driver's side headlight into a wire nut. Turn the wire nut clockwise until it is firmly attached to the wires.
Slide the stripped end of the green wire from the control box and the stripped end of the wire attached to the passenger's side headlight into a wire nut. Turn the wire nut clockwise until it is firmly attached to the wires. Slide the stripped end of the yellow wire from the control box and the stripped end of the wire that is no longer connected to the passenger's side headlight into a wire nut. Turn the wire nut clockwise until it is firmly attached to the wires.
Place a ring connector on the stripped end of the fused red wire. Crimp the ring connector securely onto the red wire. Use an open-end wrench to remove the nut from the positive terminal stud. Slide the ring connector over the stud. Thread the nut onto the stud and tighten it securely with an open-end wrench. Place the negative terminal on the negative battery post and tighten it securely with an open-end wrench.
Check the headlights and flasher for proper operation. Check all connections and fuses if the headlights or flasher fail to operate correctly.
Tips & Warnings
- Check your local ordinances for laws pertaining to the installation of flashing lights on vehicles.
- A service manual can help you identify the headlight wires in your vehicle without a circuit tester.
- Wire colors will vary with different flashers, check the documentation for your specific model before cutting any wires.
- Installing flashing headlights on civilian vehicles is illegal in many areas.
- Photo Credit Jupiterimages/liquidlibrary/Getty Images
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