big problem for such a small part

So the past two weeks have consisted of some setbacks for the MINI (for those that don't know, I drive a MINI Cooper).  First, I had to shell out a bunch of money for new brakes and rotors--not really a setback, just part of every cars general maintenance.  The parts were in, the check was cashed and my uncle, the mechanic (thank God for family members that know what they are doing when it comes to cars) was set to do the brakes/rotors on Saturday. 
Not so fast..... went to leave work on Monday the 11th and she (the MINI) won't start.  Crank, crank, crank, crank...no fire.  She sits there until Thursday.  After a lot of research and really not knowing what to do, my friend suggests I open the gas cap and put it back on and give it a try.  Guess what?  It worked!
Got it home, the brakes were done on Saturday, she ran like a champ Sunday and part of Monday.  Driving home from work Monday the 18th, she's running perfect.  I literally down shift to second gear as I am taking a left onto my street and she decides to take a dump on me.  Crank, crank, crank, crank...no fire.
I get out and try the ol' gas cap routine again.  This time, it's a no-go.  My dad comes over and the two of us throw her in neutral and manage to push her up my driveway into my garage.
After hitching a ride to and from work from my awesome grandparents for three days, stressing out that my car is going to need to be taken to the dealership so they can do their professional tricks and make me pay them boat loads of money, looking through this 1,000+ page manual

that was borrowed from a friend of a friend and finding nothing but confusing fuse options that weren't even in the right place on the car and some more stress, the problem was solved.

This small, quarter-sized 11 dollar relay was the culprit the entire time.  What exactly does it do?  I couldn't tell you.  What I do know is that the "bad" relay was switched out for the "good" relay that controls my air conditioner.  So as it is right now, my car starts but my air won't work.  I picked up the part yesterday so we should be as cool as ice as soon as my uncle or dad can plug it in!
In my next life, I am coming back as a mechanic and will have my own business. 
I could defiantly pull off that navy blue jump suit with the stitched on name badge.