2005 C230 Sport

Purchased it and noticed brake pad replacement sensor was out, went to replace the front right side one and it went fine. Go to replace left side front and there was an old sensor hanging but inserted into the brake pad. However, it was not plugged into any part of the wiring harness like the right side was. I ordered a piece of the harness for the left side thinking it was missing by the previous owner. When I go to install it I cannot find any place where it looks like it will insert. So it has me wondering if my car only uses a right side and only one brake pad wear sensor? Anyone have any idea?

In the pics below you can see the left side plug where the ABS harness plugs into it up in the wheel well. The space to the right of the plug is where the brake pad wear sensor would plug into (or at least where it does on the right side). But on the left you can see there are no wires or connectors inside of it. This all has me wondering why the previous owner would even bothering inserting the left side wear sensor into the brake pad if there was no where to plug it in?