Changing the temperature of a system at equilibrium also changes the relative amounts of reactants and products. The system counteracts the change, as Le Chatelier's Principle predicts. When the temperature is increased, the system favours the endothermic direction, because that direction takes in energy and so opposes the rise. When the temperature is decreased, it favours the exothermic direction, because that direction releases energy and opposes the fall.
If the temperature is increased, the relative amount of products at equilibrium increases for an endothermic reaction and decreases for an exothermic reaction. If the temperature is decreased, the relative amount of products at equilibrium decreases for an endothermic reaction and increases for an exothermic reaction.
Here is an example. Colourless dinitrogen tetroxide changes into brown nitrogen dioxide, and the forward reaction is endothermic. Heating the mixture at equilibrium increases the amount of nitrogen dioxide, so the mixture turns darker brown. Cooling it makes the mixture paler.
In the Haber process, the forward reaction making ammonia is exothermic. Raising the temperature therefore decreases the relative amount of ammonia at equilibrium.