Tā zài lièrì xià zhàn le sān ge xiǎoshí, zuìhòu hūn le guòqù.
He stood under the blazing sun for three hours and finally passed out.
Tips
grammar
昏 'faint' + directional complement 过去 'go over,' giving the sense of consciousness 'going away.' The complement can split around 了: 昏了过去. Compare 醒过来 (xǐng guòlái) 'come to / wake up,' which uses the opposite direction.