relay to turn off power

Had to bump this back to the top, because I think this will do what I want it to..

FIRST THE STORY:   I've got a relay that turns on an electric fan, it has a thermostatic controler that activates the relay and of coarse then the fan runs from direct power from the battery.  Now, the controller has another wire that allows you to "bypass" the thermostat, and turn on the fan manually..BUT, when I wired this up using a simple on/off switch, it blew fuse after fuse, and now it has burned up the switch. I cannot find a short, It would work for a day or two, then the fuse would blow. Now the switch no longer works, but the thermostatic control does still work...

SO here's the solution I need help with.. I want to wire a relay to turn off the thermostatic controller, and run the fan, from a switch on the dash.. This is so I can run the fan manually to cool the A/C, when the radiator is not hot enough to turn on the fan. I've already been asked, why don't I just wire the fan to the A/C so that it runs when the A/C is on?... Answer: I take long trips and don't want the fan running as I'm traveling down the highway at 70 mph, with the A/C on for 3-4 hours... Please help.. I just can't see how to wire up the relay to cut something off, and turn something on at the same time...

The relay on the controller, does it switch power or ground to the fan?   The fan will be supplied either power or ground, and get the other from the relay. Since you said it runs on power straight from the battery, I am assuming that the relay provides ground for the fan. This will be a piece of cake, I just need to know what you have to be able to draw you a picture.   This can be done with one additional relay and a switch, we won't even burn up a switch.

Thank you so much for your help..

Actually, I'm pretty sure the controller relay supplies the (+) to the fan.. Seems like I remember running a ground wire from the fan and connecting it to the ground from the controller, and then connecting all the ground wires to the fenderwell, under one screw.  I've been running the problem through my head for 3 weeks now, and I'm starting to think that the problem might have been the spike from the relay.. it has no diode, and perhaps that could have been blowing my fuses? perhaps that could have toasted my switch?.. I dunno.. I barely have relays figgured out, I sure as hell don't know much about diodes.

Ok, I'm confused.. you say that the "lack of a diode took out the switch" but the fuse blowing was not caused by it? do I have that right? This is the problem. It all worked fine for about a month before the 1st fuse blew.. the second after about 5 days, and the 3rd and 4th fuses about the same.. THEN, the switch burned up, and it hasn't blown a fuse since. I dunno..It's like the switch was shorted, but I just couldn't find any evidence of that...anyway,  I did look, and the (-) wire from the fan, absolutley goes straight to ground. so It's a sure thing the controller/relay provides (+) to the fan.

Thanks again for your help, I always find folks on here willing to help..