I have a 2008 Cadillac DTS that is running hot. There is an issue the with the cooling fan not working properly, I just replaced the complete fan assembly yesterday and the same issue persists. The fans do not run unless the AC is on, with the AC on only the passenger side fan runs, this happened with both the old fan assembly and the new one. I checked and tested the relays there good, I replaced them with new ones anyway, inline fuse looks good and tested good but I didn't replace that. I replaced the thermostat yesterday too for good measure. Coolant is good and is at the correct level in the tank, cap is good replaced the cap for good measure. Still the same problem persists the fan does not come on, I let the car idle with the AC on for 1hr until it the engine temp reached 230 (have a basic cheap OBD!! tester plugged in) the fans do not come on, let it sit for hours retried the same idle test with the AC on for 1 hr temp reaches 216 and then fluctuates between 210 and 220, however I cannot be out on the road with only one fan, I live in Florida where it is Hot AF all the time. I can't figure this out and it is driving me insane, I also tested the connectors that plug into each fan, the test good, so what is the problem? I don't get it, I probably didn't even have to replace the fan assembly but I did anyway. The only thing left I can think of is the engine temperature sensor which is located in an unreachable area on the lower back side of the engine by the firewall. Any help would be appreciated.