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.
Junction box electronics relays
The junction box electronics unit (JBE) has internal and external relays. The excitation coils on all relays are permanently supplied with a positive cable. The positive power supply for the external relays is provided via the load circuit which is to be switched through. The positive power supply for the internal relay is provided via the fused junction box electronics supply wire. All relays are controlled via the negative lead. All internal relays and the relay for wiper stage 1 and wiper stage 2 are located downstream of the fuse on the current circuit. All other external relays on the junction box electronics are located upstream of the fuse on the current circuit.
The internal relays are:
- Relay for power window drive, rear
- Relay for central-locking drive (except tailgate)
The external relays are:
- Relay for drive, rear window wiper
- Relay for drives, wiper stage 1 and wiper stage 2
- Relay for headlight washer system
- Relay for heated rear window
- Bistable relay (deactivation of closed-circuit current fault)
NO RELATED
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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.