told vs have told in a sentence [closed]
Solution 1:
I told him while suggests that you warned him as he was hiking. I have told him suggests a different timing, that your warning is relevant to the current topic but didn't necessarily happen at the same time.
Thus, if you were with him on the trail when you told him, the simple past tense is better. But if you gave him a standing warning that he later ignored, the perfect tense (I have told) is better. You can even write I had told him to emphasize that your warning was in the past.