CAN bus park brake interface
Take a reliable handbrake signal off the vehicle network to enable screens, navigation and video-in-motion functions.
What a CAN bus park brake interface does
A CAN bus park brake interface reads the handbrake or park-brake state on the vehicle network and outputs a signal that tells a head unit, screen or navigation system whether the vehicle is stationary. Aftermarket displays use it to enable functions that are only allowed when parked.
Modern vehicles use electronic park brakes and carry the state as a network message, not a switched wire at the lever. The interface reads that message and provides the park-brake feed the display expects, without cutting into the vehicle's braking wiring.
Why aftermarket screens need this signal
Many head units and monitors look for a park-brake input before they'll allow video playback, address entry or certain settings. On a vehicle with an electronic park brake there's no simple wire to give them, so the display stays locked out.
- Enables parked-only functions: the screen sees a genuine handbrake state and unlocks what it's meant to when stationary.
- Reads the electronic park brake: it works where there's no mechanical lever or switched wire to tap.
- A clean, safe install: the signal comes off the network, not from splicing the brake wiring.
- Consistent behaviour: the same approach works across an electronic-park-brake fleet.
What the park brake signal enables
A genuine handbrake feed is what unlocks safe, parked-only functions on aftermarket kit.
Aftermarket head units
Enable video, navigation entry and settings that a head unit restricts to when parked.
Rear-seat and monitor screens
Allow video playback on screens where it's permitted when the vehicle is stationary.
Navigation systems
Permit destination entry and full menu access from a parked position.
Camera and DVR systems
Combine with a reverse feed for a complete camera and recording install.
Fleet and specialist displays
Give specialist in-cab displays the stationary state they rely on.
Conversion infotainment
A reliable park-brake feed for infotainment added to van and camper conversions.
Fitting a screen that needs a park brake feed?
Tell us the vehicle and the display, and our engineers will confirm the right interface off the CAN bus.
Reference
How the park brake signal works
It reads one specific state off the network and reports it to the display.
- 1
Connect to the network
The interface joins the CAN bus and reads the park-brake message already present, with no cut into the braking wiring.
- 2
Read the park-brake state
It decodes whether the electronic or manual park brake is applied for that make and model.
- 3
Output the signal
It provides the park-brake feed the head unit or screen expects, reflecting the vehicle's true state.
- 4
Enable the display
The screen uses the signal to allow parked-only functions when the vehicle is genuinely stationary.
Which vehicles it covers
Park-brake state is carried on the CAN bus of modern cars, vans and trucks, including the electronic park brakes now common across the range. The interface reads each manufacturer's message in configuration, so one product covers a mixed fleet.
Coverage spans the common UK van and truck fleet, kept current with in-house firmware. Scorpion has built vehicle electronics in the UK since 1973.
This is a safety-relevant signal, so it should be fitted so the display only enables in-motion features where it is legal and safe to do so. The interface reports the vehicle's real park-brake state rather than a spoofed permanent input.
For a full head-unit retrofit it sits alongside the illumination and reverse feeds, so the screen dims with the dash, shows the camera on reverse, and enables parked functions correctly.
Common fitments include:
Common questions
What is a CAN bus park brake interface?
It is an interface that reads the handbrake or electronic park-brake state off the CAN bus and outputs a park-brake signal for aftermarket head units and screens, which use it to enable parked-only functions.
Why can't I wire the head unit to the handbrake?
Modern vehicles use electronic park brakes and carry the state as a network message, so there's often no mechanical switch or wire to connect to. The interface reads the network instead.
Is it safe and legal to enable video in motion?
The interface reports the vehicle's genuine park-brake state rather than a permanent spoofed input, so functions only enable when the vehicle is truly stationary. Fit and use it in line with the law and the display maker's guidance.
Will it work with an electronic park brake?
Yes. Reading the park-brake message off the CAN bus is exactly how the interface supports vehicles that no longer have a manual lever or switched wire.
Can you provide park brake with other signals?
Yes. A multi-output interface can supply park brake alongside illumination, reverse and speed from one connection. Speak to us about the install.