What does the tow light in dashboard indicate on 1999 E320?

In a 1999 E320, the tow light on the dashboard indicates that the vehicle is in tow mode, which is often used when towing a trailer or another vehicle. This mode adjusts the transmission's shift points and engine behavior to accommodate the added weight and improve performance while towing. If the light is illuminated without towing, it may suggest an issue with the transmission or towing system, and it's advisable to consult the owner's manual or a mechanic for further diagnosis.