My information is that Adventists are Binitarian. That is they do not consider the Holy Spirit a person. Is this still true?
The mainline SDA statement is, "2. That the Godhead, or Trinity, consists of the Eternal Father, a personal, spiritual Being, omnipotent, omnipresent, omniscient, infinite in wisdom and love; the Lord Jesus Christ, the Son of the Eternal Father, through whom all things were created and through whom the salvation of the redeemed hosts will be accomplished; the Holy Spirit, the third person of the Godhead, the great regenerating power in the work of redemption.
Matthew 28:19. "
Fundamental Beliefs 1931
You may find that view among the semi-arian SDA sects.
This is truly a remarkable development, especially given the strongly Arian and semi-Arian views that were so dominant in the Adventism of her day. Such views were even held by her strong-minded, forthright husband, James White, until fairly late in his life. What was somewhat curious (and in need of some further explanation) is why she never directly attacked anyone who held to this dominant Arian expression, but then seemed to be willing to go against such a grain with her own positive testimony to the full deity of Christ. Most certainly, by the time of the 1888 Minneapolis General Conference, she was clear in her understanding of the full deity of Christ and her affirmations of the Trinity. Her understanding included the clear affirmations of the eternity and equality of the Son with the Father.
Arianism, Adventism and Methodism: The Healing of Trinitarian Teaching and Soteriology</b></font></b></font>
"Our pioneers clearly held Arian or semi-Arian views in regard to the person of Christ. They understood “firstborn over all creation” (Col 1:15) and “only begotten Son” (John 3:16) in a literal sense. The Father, therefore, was first and superior, and the Son, who had a beginning sometime in eternity, was subordinate to the Father.
A corollary of this view was the belief that the Holy Spirit is an influence or the power of God, but not a person."
(Gerhard Pfandl, Biblical Research Institute, The Doctrine of the Trinity Among Seventh-day Adventists; Journal of the Adventist Theological Society, 17/1 (Spring 2006): 160-179)
Were Seventh-day Adventist Pioneers Arians or semi-Arians? — As It Reads
Significant Semi-Arian within Traditional Adventism
http://archive.atsjats.org/10Burt-SDATrinity0601.pdf
Also, SDA are sometimes confused with United Church of God
United Church of God | CARM.org