This mod has been around a little while and involves jumping two wires at the ECU to make both, the AC and cooling fans come on concurrently. Either event (cooling or air conditioner) will trigger both fans to come on instead of just one.
There are two ways to do this mod. The first way is the simplest and just involves jumping two wires. The other way is to connect a switch to the same two wires. A switch obviously allows the user to decide whether to turn dual-fan mod on or off.
This could be handy to manually regulate electrical draw on the system or for adapting to changes in climate (summer-winter) and as an excuse to buy another switch to play with because dudes love switches.
With the right parts, there will be no damage to the wiring and the mod can be undone at will but why would you do that?