Catherine and Heathcliff's visit to the Grange in Emily Bronte's "Wuthering Heights" was motivated by a number of reasons. Firstly, Catherine was invited by her father, Mr. Earnshaw, to spend some time with the Linton family in the Grange. The Lintons were a wealthy and refined family who lived in a large and comfortable house, and Catherine was eager to experience their way of life and to escape the wild and harsh existence she led at Wuthering Heights.
Additionally, Catherine's desire to experience life outside of Wuthering Heights was also driven by her dissatisfaction with her current life. She was frustrated with the limited opportunities and harsh conditions she faced at Wuthering Heights, and longed for the luxury and sophistication she believed the Lintons offered.
Furthermore, Catherine was also seeking to establish herself as an independent and intelligent woman, distinct from the rough and wild image associated with Wuthering Heights. Her visit to the Grange was an opportunity for her to prove to herself and others that she was capable of adapting to a new environment and that she was more than just a simple country girl.
Lastly, Catherine's relationship with Heathcliff was also a factor in her decision to go to the Grange. While she loved Heathcliff deeply, she was aware of the social barriers that prevented their relationship from flourishing, and saw her visit to the Grange as a way to distance herself from him and to prove to him that she was not bound to Wuthering Heights.
In conclusion, Catherine and Heathcliff's visit to the Grange in "Wuthering Heights" was motivated by a combination of Catherine's desire for adventure and independence, her frustration with her current life, her desire to prove herself as an intelligent and adaptable woman, and her relationship with Heathcliff.