W209 AMG CLK 55 Seat heater problem

[bergmjh]

2003 AMG CLK 55 The seat heater on the drivers side no longer works. Passenger side works great and that eliminates the fuses. I am able to look at the voltage signal at the seat computer. The drivers side has 4 volts no matter what I do with the switch. The passenger side shows 0 volts switch off, 6 volts at heat setting #1 and 12 volts at heat setting #2. Does anyone know how can I get a hold of a wiring diagram to see what is between the switch and the seat computer? Thanks John