Question: How do I locate ethics opinions from a bar association?

ABA Formal Opinions (1924- present) & Informal Opinions (1945- present):

• Opinions of the Committee on Professional Ethics: with the Canons of professional ethics, annotated, and Canons of judicial ethics, annotated (Smith/Annex KF 305. A2 1967) includes texts of formal opinions no. 1 -315 (1924-1966) 
• Informal ethics opinions (Smith KF305 .A2 1975) 2-vol. set that contains texts of informal opinions C-230a – 1284 (1961-1973)
• Formal and Informal Ethics Opinions: Formal opinions 316-348, informal opinions 1285-1495 (Smith/Annex KF 305 .A2 1985a) includes texts of formal opinions 1967-1982 and informal opinions 1974 to 1982.
• Formal and informal ethics opinions, 1983-1998 (Smith KF 305 .A2 2000x) Contains formal opinions 349-412 and informal opinions 1496-1530 
• ABA/BNA lawyers' manual on professional conduct (Smith KF 305 .A8 A23x) Contains informal and formal opinions 1980-present.
• Lexis Advance
  • ABA Formal Ethics Opinions 1924-present (Search "FOPIN")
  • ABA Informal Ethics Opinions 1959-2009 (Search "INFOP")
• Westlaw: Search "ABA Ethics Opinions"
  • Formal Opinion coverage begins January 1924
  • Informal Opinion coverage begins July 1961
• ABA ethics opinions are available for purchase online and can be downloaded free of charge by ABA members for one year after their issuance.

State Codes and Ethics Opinions

• National Reporter on Legal Ethics and Professional Responsibility (SMITH KF 306 .A45 N38x) contains 50 states' ethics codes and judicial opinions for some states. 
• Most state bar websites publish their own ethics opinions 

Michigan Ethics Opinions

• State Bar of Michigan website
• Michigan Ethics Opinions 1992-1996 (SMITH KFM4276.5.A2 S734 1992x) 
• Court rules of Michigan annotated (ICLE) (SMITH KFM4729 .A2 1991x) Chapter 10 includes the MRCP and MCJC.