Powering radar (and other gadgets) from TSS. Dongar preview (USB-C power adapter that hooks up to your lane trace sensor computer)

Important Disclaimer – Lane-Trace System Power Adapter

Fuse Protection and Low Current Draw
The lane-trace power circuit is protected by a dedicated fuse in the vehicle’s fuse box (just like your other accessory circuits). This fuse acts as a built-in safety mechanism. In the unlikely event of a fault (such as a short or overload), the fuse will blow and cut power to prevent any damage – safeguarding your vehicle’s wiring and electronics. During our testing, we verified that the adapter’s power draw remains well within safe limits for the circuit. We used a fuse-to-multimeter adapter together with a USB load tester to simulate a constant 1.5 A @ 12 V USB-C device load on the adapter. The measured current at the fuse box was less than 2.5 A (the test load and everything else on that circuit, combined) with no large transients observed, even when activating or deactivating lane trace and features. This low amperage confirms that the additional load is minor, placing little strain on the existing circuit. In real-world terms, a 1.5 A draw at 12 V is roughly 18 watts – comparable to a standard car USB charger or a couple of interior LED bulbs. The factory fuse for the lane-trace system is rated well above this level, so normal operation stays comfortably below the fuse threshold. The result of our load test demonstrates that using this adapter has a negligible impact on your vehicle’s electrical system. Its supplying power within the margins that Toyota/Lexus has already provided for. We emphasize that if anything does go wrong (for example, a direct short in the adapter or connected device), the most likely outcome is simply a blown fuse – an event the car is designed to handle by design, with no further damage downstream. Replacing the fuse (and addressing whatever caused it to blow) would restore the circuit to normal. The adapter also has built-in over-current and over-voltage protection, ensuring a second layer of safety for your peace of mind.

Vehicle Alerts as an Additional Safety Net
Toyota and Lexus vehicles are engineered with robust self-diagnostic features. In the event of any malfunction or abnormality in the lane-trace assist system’s operation (for instance, if the camera were to lose power or a fuse blows), the vehicle will immediately alert the driver via dashboard warnings or messages. The instrument cluster’s multi-information display is programmed to show warnings for any system malfunctions so if the lane-trace camera or its power supply is ever compromised, you will get a clear, noticeable warning (such as a “System Malfunction” or similar message accompanied by various status symbols). This provides an extra margin of safety: you would know right away if something isn’t functioning as expected. In our scenario, because the adapter does not affect data lines and only taps power, a malfunction would typically only occur in extreme cases like a short circuit causing a fuse to blow. Should that happen, the lane-trace system would stop receiving power and the car would promptly display a fault alert for the driver. Address the issue (e.g. replace the fuse or remove the adapter) or consult your dealer before continuing to operate the vehicle.


Example Warning Messages. Observed when the fuse pops or the harness connection fails:

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