Just back to my home office and able to look at the ETM for the '83-'85 SL.

The O2 light's connection is to the speedometer. There is no connection to the sensor or to the control unit. Therefore it is impossible for the light to indicate the sensor's condition.

The last step in the instructions in the Maintenance Section for O2 sensor replacement:

"Remove oxygen sensor warning lamp bulb."

I continue to believe it is a one-shot deal at 60K on the clock.

The warning lamp in the 560SL is controlled by the CIS unit.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe