I have the same question !
under the hood. top left
Waiting for the answer.
Where are the jump start terminals under the hood on a 2003 e320
If not under the hood or in the trunk it will be located under the back seat passenger side
To open the hood of a 1999 Mercedes-Benz E320, first, locate the hood release lever inside the car, which is typically found on the driver's side under the dashboard. Pull the lever to release the hood latch. Next, go to the front of the vehicle, slide your hand under the hood's center, and find the secondary release latch. Push this latch to the side while lifting the hood to fully open it.
Under the dash just to the left of the steering wheel. It is a red handle on 04s and 05s.
In the 2002 Mercedes-Benz E320, the hood release lever is located inside the vehicle, on the driver's side. Specifically, it can be found under the dashboard, near the left side of the steering column. Pulling this lever will release the hood latch, allowing you to lift the hood. Once the hood is released, you can secure it with the safety catch located at the front of the hood.
On my 1998 E320 there are 1. fuses left of the instrument cluster facing the door, 2. fuses near the battery, and 3, under the hood on the driver's side
after you open the inside hood release there is a little black piece of plastic in the grill push it to the left or right or you may have to pull it straight out different years did it different.
The hood release on my 1998 E320 wagon is under the dash next to the drivers door. It is also listed in the Owner's Manual.
Under the driver's side dashboard, just to the right of the hood release lever. It is covered by a hinged plastic door.
On my 2003 e320 it is located just below the steering wheel, on the panel by your knees. It is red!