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Installation

Wire the cut-off relay

The optional fourth wire that lets you stop an asset from your phone.

7 min read
Never cut a running engine

Wire the relay into the STARTER circuit, not the fuel pump or ignition of a moving asset. Killing a boat’s engine in a channel or a vehicle’s in traffic creates a hazard you are liable for. Cut-off stops something being started or restarted — that is the job it is for.

The tracker’s white lead is a low-current output. It does not switch a starter directly; it switches a standard automotive relay, and the relay does the work.

Cut-off relay wired into the starter circuitA normally-closed relay is fitted in the starter solenoid trigger wire. Its coil is driven by the tracker's white lead. With no command the contacts stay closed and the asset starts normally; when the cut-off command lands the coil pulls, the contacts open, and the starter cannot be triggered. Because it is normally closed, a dead or removed tracker leaves the asset able to start.Key switchstart positionRelay — normally closedclosed at restopens when energisedcoilStartersolenoid triggerTrackerwhite lead outputFrom your dashboardRELAY,1# → cutRELAY,0# → restoreWhy normally closedA dead or removed tracker mustnever leave the asset immobilised.Cut-off stops a START, never arunning engine.
The relay sits in the starter trigger, not in the ignition of a moving asset, and it is normally closed so a failed tracker can never strand a customer.

The circuit

  1. 1
    Pick the circuit to interrupt

    The starter solenoid trigger wire is the usual choice: the engine will crank-and-do-nothing, or not crank at all, and nothing is at risk while it is running.

  2. 2
    Fit a normally-closed relay in that circuit

    Normally closed means the asset starts exactly as it always did when the tracker is doing nothing — a dead or removed tracker must never leave the asset immobilised.

  3. 3
    Drive the relay coil from the tracker’s white lead

    White to the coil, coil’s other side to ground. When the command lands, the tracker pulls the coil and the contacts open.

  4. 4
    Fuse the relay’s feed

    Same reasoning as the power lead.

  5. 5
    Test it twice

    Once from the dashboard with the asset parked and safe: cut, confirm it will not start, restore, confirm it starts. Then again a week later, because a relay you have never tested is a relay you do not have.

Using it

From the map, open the asset and use the cut-off control. The dashboard asks you to confirm, because it should. Restoring is the same control the other way. The commands travel over the tracker’s live connection, so the asset must be online for either to land.

ActionWhat is sentEffect
Cut powerRELAY,1#Relay energised, circuit opened, asset cannot start
Restore powerRELAY,0#Relay released, circuit closed, asset starts normally
Geofences can do this automatically

A zone can be set to cut power on entry — useful for a hard boundary a rental must never cross. Turn it on deliberately, and only where an automatic immobilisation is safe.

NextNext: geofences and zones
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