Kill Switch Relay Mod (Headshot Trigger)
A safer, more reliable way to implement the Death Racer headshot kill switch using a relay.
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A safer, more reliable way to implement the Death Racer headshot kill switch using a relay.
Last updated
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This page outlines a reliable relay-based solution for implementing the classic headshot kill switch used in Death Racer battles. When the racer figure's head is knocked off, a switch is released, triggering a shutdown of the RC receiver and rendering the vehicle inoperable — the battle is over.
🎯 Gameplay Objective: Knock off the opponent’s head to kill their vehicle.
The "head = kill" mechanic is standard in Death Racer builds. However, the typical method — routing battery power directly through a mechanical switch — has proven unreliable and prone to burnout, especially with 15–20 amp toggle switches.
This guide introduces the relay mod fix, as discussed in theory by Jeremy (M86 Toys) on , and will be implemented in upcoming streams using this documentation.
Builders often run the main battery voltage directly through the switch
Most toggle or magnetic switches used are rated 15–20 amps, under rated for the potential amp load.
Death Racer power setups can spike higher, leading to switch failure, overheating, or fire risk. Spikes can happen when resistance is applied to motors driving the death racer.
This puts the entire receiver system at risk and leads to inconsistent kills
Instead of routing full power through a switch, this method uses a low-power switch to control a relay, which handles the high current load.
A normally-open switch is placed under the Death Racer’s head
When the head is attached, the switch closes and activates the relay
The relay connects the battery to the RC receiver
When the head is knocked off, the switch opens → the relay cuts power → the vehicle dies
⚠️ This isolates the mechanical switch from the full battery current and dramatically increases reliability and safety
1x Relay module (DC 12V automotive relay, 40amp recommended)
1x Normally-open switch (original switch designated for the death racers)
Wire, connectors, heat shrink
Switch is closed when head is on — relay stays active — receiver has power
Switch is open when head is knocked off — relay cuts — vehicle is dead
Mount the switch in a way that the figure’s head holds it closed
Use a press-fit, snap-in, or magnet-based head that reliably pops off on impact
Secure the relay in a protected spot near the battery
Keeps high current off fragile switches
Prevents melted switches or mid-match failures
Increases reliability and reproducibility of kills
Makes builds tournament-ready
The final wiring demo, mounting technique, and live test of this relay-based system will be featured in an upcoming LeeMerie3D stream. This wiki page will be updated with:
Video tutorials
STL relay mounts
Printable wiring diagrams
Troubleshooting guide
If you’ve built this mod successfully or have refinements, consider contributing back to this page or submitting photos, diagrams, or footage of your working rig!
Jeremy (LeeMerie3D) explained this fix on . Watch the live comments by "MalaMaker" explaining this addition.