Initial Inspection and Diagnostic Overview
DIAGNOSTIC STARTING POINT - HEATING, VENTILATION AND AIR CONDITIONINGThe heating, ventilation and air conditioning (HVAC) system is divided into two sections. The first, Heating, Ventilation and Air Conditioning, has all procedures that pertain to a HVAC component or function that are not specifically associated with the manual control system. The second, HVAC Systems-Manual, has all procedures specific to the manual control system.
For systems with DTCs, begin the system diagnosis with Diagnostic System Check - HVAC Systems - Manual.
The Diagnostic System Check will provide the following information:
- The identification of the control modules which command the system.
- The ability of the control modules to communicate through the class 2 serial data circuit.
The use of the Diagnostic System Check will identify and lead the technician to the correct diagnostic procedure.
Review the Description and Operation information to help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing
the Description and Operation information will also help you determine if the condition described by the customer is normal operation. The HVAC Description and Operation information is divided into:
- Air Delivery Description and Operation in HVAC Systems-Manual
- Air Temperature Description and Operation in HVAC Systems-Manual
The Air Delivery Description and Operation contains the following topics:
- HVAC Control Components
- Air Speed
- Air Distribution
- Recirculation Operation
The Air Temperature Description and Operation contains the following topics:
- HVAC Control Components
- Heating and A/C Operation
- Engine Coolant
- A/C Cycle