When I turn the air conditioning on in my 2013 GMC Terrain there is the smell of mold. Apparently the air conditioner doesn't get rid of any moisture left after using it.

There is a procedure for this condition. GM says to flush the core with a cleaning agent they sale. I have found Lysol Fresh scent does a much better job of curing the condition.Spray the Lysol in the outside air intake vent while the vehicle is running with it set to max a/c and fan speed also on max. It will take about 1/4th can to fully clear the mildew smell and stop it from growth. When parking the vehicle always put it in max a/c position so the fresh air outside the vehicle will dry out the coil.