Why do cooling fans on a 1999 Cadillac deville work only when the ac is on?

In a 1999 Cadillac DeVille, the cooling fans are designed to operate primarily when the air conditioning (AC) is on to help dissipate the heat generated by the AC system. When the AC is activated, the fans draw air through the condenser, ensuring efficient cooling. Additionally, the fans may also engage to help regulate engine temperature, but if they're only functioning with the AC on, it could indicate a problem with the engine temperature sensor or the fan relay. Regular maintenance and diagnostic checks can help identify any underlying issues.