When I turn the ignition key to on the speedo needle vibrates for about 5 seconds. This happens when I turn off the engine also. When turning off, after about 5 seconds there is a relay clicking sound behind the dashboard and it stops vibrating. On startup the water and gas gauges do not work until the vibrating is over and then they pop up to the correct readings. Because this car had CAN B failure which required replacing the SAM unit and the window control and sunroof control modules I am worry that this condition may damage those modules again or maybe others. Any ideas? So far I cannot find anything when searching. No codes are being generated. Thanks in advance for your help!

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1984 300CD (sold)
1973 220DPK 4 spd (died)
1978 350SL 4 spd gray market
2003 SLK32 AMG
1988 300CE (sold)
1997 E420 (Totaled)
1998 E320 Wagon