On my 300SDL there is a little black unit with a dial and numbers on it on the driver side in the engine compartment, just behind the fuse box. It has numbers on it from 1 to 8 (I believe) and can be adjusted by pulling up and rotating it. Does anybody know what this is and what the adjustments do?

__________________
Mahalo and Aloha,
S. L. "Red" Pike, Naval Architect/Marine Engineer, USCG Licensed Chief Engineer (Steam, Motor, and Gas Turbine)
Former nuc bubblehead (boomers)
"Sustained superior performance through continuous incremental improvement."

1987 300SDL White w/ Gray Leather interior, 160K (mine)
2009 Nissan Murano (leased - wife's)