Your car should have 2 fans. When wired from the factory, they will both come on at the same time, usually controlled by either the PCM or the HVAC system if you have autoclimate control.
When A/C is requested, the fans will goto LOW speed and depending how hot it is, the fans will goto HIGH.
When the PCM detects a hot engine temp, 212F, the fans will goto LOW, if the PCM sees 226F, the fans will goto HIGH.
With that said, I'm wondering if someone bypassed the existing system because they thought the fans didn't come on. We have had many a member coming here asking about that.
The wiring should come from the drivers side at the bottom of the radiator, goto the drivers side fan, then continue to the passenger side fan. Remove any and all funky NON-factory wiring. If need be, take pictures and post them.
1997 Pontiac Bonneville SEi-SCRAPYARD
2000 Chevrolet Blazer LT 4X4 4.3L
2002 Chevrolet *-10 LS Ext Cab 4X4 5.7 V8