Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Cigarette Lighter Battery Charging Function
A trickle charger can also be connected to the cigarette lighter. However, the cigarette lighter is supplied by the body-zone consumer isolation circuit (VA-K) via a relay.
If the "terminal R Off" signal is present for more than 60 minutes, that relay will be switched off by the consumer shutdown function. That would mean that a charger connected to the cigarette lighter would be disconnected from the battery.
To prevent this, the consumer shut-down function can be deactivated. This is performed by the following procedure:
Slide the battery switch off and on again twice within two seconds. Starting with the battery switch in the ON position, switch to OFF, Switch ON, Switch OFF and end with the switch in the ON position. Do this within 2 seconds, an the trickle charger can be used to charge the battery through the cigarette lighter.
The function is cancelled by: "terminal 15 On", switching the battery switch from "OFF" to "ON" or failure of the battery voltage to reach 12.6 V after 6 hours of charging.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.