[BNaylor]

Welcome to AF.

Sounds like a possible short which could be due to moisture. The cooling fan relays are hot at all times on one side of the coil. So if the relay input which comes from the PCM module is shorted the respective fan will run. The relay has to be energized to turn the fan on. An area of concern would be the engine compartment fuse box. Check there for water and try drying it out since the cooling fan relays are located there.