Why does your jeep Cherokee 1997 limited edition blow cold air out even after changing the heater matrix and thermostat?

The HeaterTreater is an after market kit that solves heater and AC for the Jeep Grand Cherokee and Laredo. It is much cheaper than the dealership fix and is easy to install. For diagnosis and info, check out www.heatertreater.net or search eBay for "heatertreater".