Hi Sally-Anne and welcome
With a bit of googling, I found this site has some wiring info but not sure it is useful and the full-size photos are no longer available. Google Rancilio Z9 and there are plenty of hits. You might try this page on the Rancilio site. It doesnt display your model but the wiring may be similar??
Another suggestion would be to try contacting Coffee parts one of the sponsors listed on the left. They may have something