Iv watched this on youtube check the roof buttons engaging is it lit then its in yhe boot behind pannels theres the pump im sure its hydrolic there should be a relay switch on the side you can get these checked before buying new check fluid lvls then if not its the pump itself easyvto swop out but expensive even secobhand cost 200 pound
Wiring, sc hematic, electrical diagrams etc are basic contents of these online books they here on this website www.reliable-store.com Must check it out