That’s correct–the Holy Spirit would lead him to discover the truth if he were reslolved to provide a definitive judgment. Here’s how St. Francis de Sales explains it (see especially the last paragraph, but the whole thing is good):
[quote=St. Francis de Sales]And in fact everything a king says is not a law or an edict, but that only which a king says as king and as a legislator. So everything the Pope says is not canon law or of legal obligation; he must mean to define and to lay down the law for the sheep, and he must keep the due order and form. Thus we say that we must appeal to him not as to a learned man, for in this he is ordinarily surpassed by some others, but as to the general head and pastor of the Church and as such we must honour, follow, and firmly embrace his doctrine, for then he carries on his breast the Urim and Thummim, doctrine and truth. And again we must not think that in everything and everywhere his judgment is infallible, but then only when he gives judgment on a matter of faith in questions necessary to the whole Church; for in particular cases which depend on human fact he can err, there is no doubt, though it is not for us to control him in these cases save with all reverence, submission, and discretion. Theologians have said, in a word, that he can err in questions of fact, not in questions of right; that he can err extra cathedram, outside the chair of Peter, that is, as a private individual, by writings and bad example.
But he cannot err when he is in cathedra , that is, when he intends to make an instruction and decree for the guidance of the whole Church, when he means to confirm his brethren as supreme pastor, and to conduct them into the pastures of the faith. For then it is not so much man who determines, resolves, and defines as it is the Blessed Holy Spirit by man, which Spirit, according to the promise made by Our Lord to the Apostles, teaches all truth to the Church, and, as the Greek says and the Church seems to understand in a collect of Pentecost, conducts and directs his Church into all truth: But when that Spirit of truth shall come, he will teach you all truth or, will lead you into all truth (John xvi. 13). And how does the Holy Spirit lead the Church except by the ministry and office of preachers and pastors? But if the pastors have pastors they must also follow them, as all must follow him who is the supreme pastor, by whose ministry Our God wills to lead not only the lambs and little sheep, but the sheep and mothers of lambs; that is, not the people only but also the other pastors: he succeeds S. Peter, who received this charge: Feed my sheep. Thus it is that God leads his Church into the pastures of his Holy Word, and in the exposition of this he who seeks the truth under other leading loses it. The Holy Spirit is the leader of the Church, he leads it by its pastor, he therefore who follows not the pastor follows not the Holy Spirit.
But the great Cardinal of Toledo remarks most appositely on this place that it is not said he shall carry the Church into all truth, but he shall lead; to show that though the Holy Spirit enlightens the Church, he wills at the same that she should use the diligence which is required for keeping the true way, as the Apostles did, who, having to give an answer to an important question, debated, comparing the Holy Scriptures together; and when they had diligently done this they concluded by the: It hath seemed good to the Holy Spirit and to us; that is, the Holy Spirit has enlightened us and we have walked, he has guided us and we have followed him, up to this truth. The ordinary means must be employed to discover the truth, and yet in this must be acknowledged the drawing and presence of the Holy Spirit. Thus is the Christian flock led,-by the Holy Spirit but under the charge and guidance of its Pastor, who however does not walk at hazard, but according to necessity convokes the other pastors, either partially or universally, carefully regards the track of his predecessors, considers the Urim and Thummim of the Word of God, enters before his God by his prayers and invocations, and, having thus diligently sought out the true way, boldly puts himself on his voyage and courageously sets sail.