polarity change, need some reassurance

I have reviewed the relays section of the site, and it was just as informative as everything else-awesome job. However I would just like to be positive that I understand this. I have a controller that has a 12v + terminal that I need it to activate a device that takes a 12v - signal. So with that being said: I run a wire from the pos terminal, and connect it to 86. I ground 85 and 30, and that will give me my neg activation signal on 87?

Thanks so much in advance. This will be my first time changing polarity for any reason, and like I said, I'm seeking some reassurance from more experienced individuals.

Thanks.