Evaporator frost prevention control logic for front and rear integrated hvac system

An HVAC system for a vehicle comprising:

• a housing;
• a front HVAC unit housed in the housing and having a front blower, the front blower generating an airflow through a front airflow path;
• a rear HVAC unit housed in the housing and having a rear blower, the rear blower generating an airflow through a rear airflow path;
• a separating wall separating the front HVAC unit from the rear HVAC unit;
• an evaporator having a first portion and a second portion;
• and
• a heating core having a first portion and a second portion,
• wherein the airflow in the front airflow path flows through the first portion of the evaporator and the airflow in the rear airflow path flows through the second portion of the evaporator, and
• wherein the separating wall prevents the airflow through the first portion of the evaporator from mixing with the airflow through the second portion of the evaporator.

A method of operating an HVAC system for a vehicle comprising the steps of:

• providing a front HVAC unit having front blower, a rear HVAC unit having a rear blower, an evaporator having a first portion and a second portion, and a heating core;
• switching the rear blower to an OFF position;
• automatically operating the rear blower at a minimum voltage;
• and
• automatically operating the rear HVAC unit such that a temperature of airflow exiting the rear HVAC unit matches a temperature inside the vehicle.