You do not say when Jeanette Johnson was last known to be living; whether "Johnson" is her maiden name; her approximate age --- although apparently old enough to have been married & divorced.
Under the above name she does not appear in SSDI, as deceased in FL nor obtaining SSN in CA --- but that is from inconclusive records, incomplete and only for deceased persons.
16 current phone listings in FL, only one in Broward County: Jeanette Johnson, 701 Vista Isles Dr, Sunrise, FL 33325; Phone: 954-424-6698
27 deaths of "Jeanette Johnson", both white & other, in FL from 1980-1991.
You will probably need the services of a 'private eye', perhaps beginning with drivers' license records.For someone with access to Broward County Courthouse, records of any traffic citations may be discovered on computer.Auto insurance companies have access to national drivers' license records.