How do you replace a fan belt of a Mercedes ml 270 cdi 2003 model?

To replace the fan belt on a 2003 Mercedes ML 270 CDI, start by disconnecting the negative battery terminal for safety. Then, locate the tensioner pulley and use a wrench to release the tension on the old belt. Remove the old belt, routing the new belt according to the belt diagram typically found in the engine compartment. Finally, ensure the belt is properly seated on all pulleys, reapply tension, and reconnect the battery.