Answer
Aug 04, 2025 - 05:01 PM
This is a common issue with the Mercedes R129. The battery is in the trunk, but when it’s dead, the electronic trunk release won’t work — so it seems like a catch-22.
Thankfully, Mercedes built in a solution:
- Open the hood (bonnet).
- On the passenger side (right-hand side), look for a red plastic cover — that’s the positive jump terminal.
- For ground (negative), use any clean metal point on the engine or chassis.
- Connect a battery charger or jump pack to these terminals.
- Once power is restored to the vehicle, the trunk should open normally via the key or central locking.
Important: Do not try to feed power into random fuses or wires — use the designated under-hood terminal only.
