My wagon doesn’t have HK but I’m pretty sure there’s a subwoofer back there. Bass is amazing if it’s coming through the tiny door speakers! How much paneling has to come off to see the connector?

I see a loose fiber optic connector above the battery but I figure it’s for an option I don’t have. My side panels have netted storage pockets where better equipped wagons have side panels that allow more modules.

Sixto
05 E320 wagon 222k miles
99 SL500 69k miles

 

It's just the panel on the passenger side that u take off and it's right there

 

I'll be darned, there's no subwoofer in my wagon! There's a fiber optic connector with no loop and some extra wires. Further aft there are a couple of open co-ax connectors which don't look like they're for audio equipment.

EPC shows dozens of rear end cable harnesses that run between the rear SAM/AGW and right side of the cargo area. I guess HK equipped wagons have a different harness. I did some sleuthing and discovered the following:

• VIN WDBUH83JX5X180906 is a 2005 E500 wagon with no HK system. The side panel has no subwoofer grill. EPC says the rear harness is 211-540-80-32 (item 100 below).
• VIN WDBUH83J05X172619 is a 2005 E500 wagon with HK system. The side panel has a subwoofer grill. EPC says the rear harness is 211-540-81-32.

Seems to me you can run wires from the rear SAM/AGW to the sub or raid a wrecking yard with a 2005 E500 wagon with HK system. Maybe any year S211 with HK has a harness you can use. New harness is NLA. Caveat: This is all conjecture on my part. I don't know that a harness will make this plug-n-play for you. There might be another section between the rear SAM/AGW and this harness.

Sixto
05 E320 wagon 223k miles
99 SL500 69k miles