Do Truck Caps Need a Brake Light?

Truck caps, also known as camper shells, provide extra storage space and weather protection for pickup trucks. But do these popular truck accessories require a brake light? The short answer is yes – truck caps need to have a working third brake light installed.

Why Brake Lights Are Necessary on Trucks and Truck Caps

Brake lights serve an important safety purpose on all vehicles, including trucks. When you step on the brake pedal, the brake lights immediately illuminate to alert other drivers that you are slowing down. This allows the vehicles behind you to react accordingly.

The National Highway Traffic Safety Administration (NHTSA) states that brake lights are required on trucks for the following key reasons:

  • Visibility – Brake lights make your vehicle more visible and noticeable when stopping. This is especially important on large trucks.
  • Clarity – Brake lights clearly indicate when you are braking versus just slowing down. This enables other motorists to react faster.
  • Communication – Brake lights give a clear signal that you are actively braking to drivers behind you.
  • Safety – Brake lights prevent accidents by giving advanced warning that the vehicle is stopping.

Based on these important visibility and safety factors, federal regulations require at least two working brake lights on all motor vehicles, including trucks.

The Federal Motor Vehicle Safety Standard No. 108 specifies the legal lighting requirements for all automobiles and trucks operated in the United States.

This federal standard mandates that all trucks have two red brake lights installed on the rear of the vehicle. Additionally, trucks manufactured from 1985 onward require a third brake light – also called a center high mount stop lamp – installed higher in the center rear.

The NHTSA has explicitly stated that truck caps also need a brake light if the truck has one. This third brake light on the truck cap provides added visibility and meets the federal legal requirement.

Some of the key brake light requirements for trucks and truck caps under FMVSS 108 include:

  • Minimum two red brake lights on the rear, placed symmetrically on each side
  • Center high-mounted stop lamp for vehicles made after 1985
  • Brake lights must be visible from 300 feet in normal sunlight
  • Brake lights must activate when service brakes are applied
  • Brake lights require SAE J586 certification

In summary, if your truck has two standard brake lights, adding a third brake light on the truck cap is mandatory according to NHTSA regulations.

Do All Truck Caps Need a Third Brake Light?

The short answer is yes – all truck caps made after 1985 are legally required to have a third brake light installed. This applies to both camper shells and other truck cap styles like fiberglass tops.

However, for truck caps manufactured before 1985, the rules are slightly less definitive. The NHTSA states that “it is advisable, but not legally mandatory” to add a high-mounted stop lamp on older truck caps.

Still, most auto safety experts strongly recommend installing a third brake light on any truck cap, regardless of age. Even if your older truck cap may not be legally required to have one, choosing to add a brake light greatly improves visibility and safety.

Options for Adding a Third Brake Light to a Truck Cap

Thankfully, there are many options available for conveniently adding a third brake light to your truck cap:

  • Integrated cap brake lights – Many modern truck cap models come with a center high-mount stop lamp already installed above the rear window. This integrated truck cap brake light connects to the electrical system and activates with your brakes.
  • Surface mount lights – Adhesive surface-mount brake lights can stick directly onto the exterior of your truck cap. They tap into your existing wiring to function as a third brake light.
  • Wired cap lights – For a professional appearance, you can wire a brake light directly into the truck cap. This involves cutting a hole for a lighting fixture and splicing into the brake light circuit.
  • Magnetic lights – Magnetic truck cap brake lights affix to the roof of your cap magnetically. This makes wiring simple, allowing you to connect the light’s wire to your truck’s brake light circuit.
  • Wireless LED lights – New wireless and battery-powered LED brake lights stick or magnetically affix to the truck cap. They sense when the truck brakes via a wireless signal or motion sensor.

With multiple options like these, it’s relatively easy and affordable to add a third brake light to any truck cap.

How to Wire a Third Brake Light on a Truck Cap

If your truck cap doesn’t have an integrated brake light, wiring one in is straightforward:

Steps for Wiring a Third Brake Light on a Truck Cap:

  1. Choose a 12V LED brake light fixture designed for truck caps. Surface-mount and flush-mount lights are common choices.
  2. Select a location centrally on the rear of the truck cap. It should be visible from behind and not blocked by any racks.
  3. Turn off the truck battery to avoid shocks when wiring.
  4. Drill a small hole into the selected area and feed the light’s wiring through it.
  5. Tap into the brake light circuit at the rear of the truck. Connect the light’s power wire to the brake light power source.
  6. Ground the light’s ground wire to bare metal in the truck bed or to an existing ground bolt.
  7. Secure all wires neatly under the truck cap trim. Avoid pinching wires.
  8. Affix the third brake light assembly securely to the pre-drilled hole using its mounting hardware.
  9. Seal any gaps or openings with silicone to prevent water intrusion.
  10. Reconnect truck battery power and test brake light operation.

With proper connection to the brake light circuit, the new LED cap light will illuminate alongside the existing truck brake lights. Installation only takes about 1-2 hours for most DIYers.

Benefits of Adding a Third Brake Light

Installing an additional brake light in the center upper area of your truck cap provides many important benefits:

  • Increased visibility – An elevated brake light stands out clearly compared to lower lights that can be blocked from view by other vehicles.
  • Faster reaction time – Studies show a third brake light decreases following driver reaction time by around 0.2 seconds. This big improvement in response can prevent collisions.
  • Legal compliance – Having the proper brake lights prevents you from being pulled over and cited.
  • Brighter stop warning – LED brake lights are far more intense than old filament bulbs, so they grab attention.
  • Safer towing – A cap brake light is critical for visibility when towing trailers that can obscure the truck’s factory brake lights.
  • Resell value – Upgrading to meet safety standards improves resale value for your truck and cap.
  • Peace of mind – Knowing your rig meets all lighting regulations provides comfort and confidence.

Adding a truck cap brake light takes little time and money but pays big dividends in safety. It should be one of the first upgrades you make after installing a new truck cap. Proper lighting is critical – don’t take risks by neglecting brake lights.

Common Questions About Truck Cap Brake Lights

Do I need a brake light if I only occasionally drive with the truck cap on?

Yes – even if the truck cap is only mounted some of the time, it must meet federal lighting requirements whenever you operate the truck on public roads. The same brake light rules apply.

My truck and cap are antique – do I still need to add a brake light?

For trucks and caps older than 1985 that originally did not have a third brake light, it is not officially mandatory. However, adding a stop lamp should still be strongly considered for safety, even on vintage rigs.

Can I tap into the cargo light circuit instead of the brake lights?

No – the third brake lamp must operate from the brake light circuit to properly activate when you step on the brakes. Tapping into a different lighting circuit is not compliant.

What color must the truck cap brake light be?

Red. Only red lights are permitted for brake lamps under federal regulations. Other colors like white can only be used for auxiliary lighting on trucks.

Will a bike brake light work for my truck cap?

Bike lights often lack the brightness, reliability, and weather sealing required for automotive use. Invest in a professional, SAE-rated LED brake light made specifically for truck caps.

Can I mount the third brake light below the window rather than above?

For maximum visibility, the brake light should be center-mounted above the truck cab window. Lower mounting is not advised, as the light can be obscured from trailing drivers’ view.

How difficult is it to wire in the brake light myself?

With basic tools and wiring knowledge, installing a cap brake light is a straightforward 1-2 hour project for most DIYers. The wiring is simple – only a power, ground, and tap into the brake circuit is required.

Will a magnetic truck cap light stay attached while driving?

Yes, high-quality magnetic brake lights use very powerful neodymium magnets. These safely keep the light firmly attached at any speed. Avoid cheaper lights with weak magnets.


Adding a third brake lamp may seem like a hassle or unnecessary expense. However, the relatively small investment in buying and installing an extra stop light for your truck cap provides outsized dividends in road safety.

Truck caps can sometimes obscure brake light visibility from vehicles behind you. And unsafe or non-working lighting is one of the leading causes for traffic stops and citations.

Taking the time to properly install a supplemental brake light demonstrates your commitment to compliance, visibility, and accident prevention. So invest in a quality truck cap brake light and drive with peace of mind knowing your truck meets all federal safety standards. Your truck’s lighting isn’t an area to cut corners or try to save money. Proper brake lights truly save lives!

Similar Posts