I bought a used company pickup from the company I work for and it came with a Jordan Mark IV brake controller in it. I can't seem to find much information about this controller. I don't think anyone has discussed this particular model here on PBB. All I know about it is it has an adjustment for braking intensity and the front of it is just a big red button that makes a relay under the hood click.
All the discussion about Jordan controllers on here talks about how their cable actuated, but mine isn't, it has no provision for a cable to attach to the controller.
I'm pretty sure it works as the truck was used to tow skid steers occasionally and the controller was professionally installed. The only time I've pulled a trailer with brakes I only had a 1,000lb load on it so I couldn't even tell if it was working or not.

I know nothing about this controller, can anyone enlighten me about how it works? How can I make sure it's working?

It's likely the pre-curser to the Ultima.... I have an Ultima.

Call Jordan, ask him... he usually answers the phone... (888) 828-1893