wiring of 86 Chevy Celebrity radiator fan relay?

2.8 liter V6. Radiator fan won't run, replaced relay and sensor/ switch. I understand it's supposed to run when AC on or temp over some value. I can jumper the 2 big wires in the relay plug (thereby manually doing the job of the relay) and the fan runs fine. How exactly is the fan relay configured? There are 2 smaller wires that somehow operate the coil of the relay to pull it in. We smoked the relay trying to pull the coil in with +12 volts before we knew how it's configured. Replaced it and don't want to repeat that. Is there something else involved, like a computer? If so, we'll probably just jumper the fan itself (2 big wires mentioned above, red and red/ black) with a big toggle switch on the dash, or jumper the relay on with a smaller switch on the dash, if we can figure out how the relay is supposed to work. Is it +12V being supplied from somewhere, or is it a ground being supplied from somewhere? Color coding of the wires?

Thanks.