Useful post from DAC on the pinouts for the radio: After much investigation, I’ve been able to replace the radio in my vehicle. Unfortunately either Crutchfield’s research on the ML320 is out of date or was incorrectly done in the first place so I wound up throwing out Crutchfield’s adapters and starting from scratch. There are two major discrepancies between my vehicle and Crutchfield’s data. First, the adapter harness they provide which is suppose to plug directly into the factory harness does not fit. The adapter they provided is intended for VW and Audi. Both it and our vehicle harness uses a single plug made of two halves of 8 pin each. The 8 pins of each half are arranged the same; however, the two halves are spaced differently. In order to fit the wiring harness into the adapter, major modifications must be done to the factory harness’s plug. Rather than do these modification, I replaced the factory plug with a standard Molex connector. The second issue deals with the antenna. The antenna in the ML320 uses a booster requiring power. Crutchfield said the power to the booster was provided through the center lead of the antenna wire, and provided an adapter to support this function. Power is not supplied through the center lead of the antenna wire; instead, there is a dedicated wire in the wiring harness from the radio which supplies power to the antenna booster. I hooked this lead up to the power antenna wire of my new radio. The following diagrams show the pinouts of the standard factory radio of the ML320, the view is into the radio or into the tail of each plug: ---------------- | 1 2 3 4 |o | 5 6 7 8 | ---------------- Power 1 Brown Ground 2 White Illumination 3 Red Battery 4 Tan Antenna 5 Pink Ignition 6 N/A 7 N/A 8 N/A Speakers 1 Orange LR- 2 Green LF- 3 White RF- 4 Gray RR- 5 Pink LR+ 6 Blue LF+ 7 Tan RL+ 8 Red RR+ WARNING: Removal of the factory unit requires a special tool. Substitution may damage the retaining clips making the radio impossible to remove without dismantling the dashboard. I think the tool should be a flat blade tapered at one edge. Insertion of the tool with the non-tapered edge toward the outside will move the clips in and release the factory radio.