Symptoms - HVAC Systems - Manual

Symptoms - HVAC Systems - Manual

Important: The following steps must be completed before using the symptom tables.


1. Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) before using the Symptom Tables in order to verify that all of the following are true:

* There are no DTCs set.
* The control module(s) can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions. Refer to Air Delivery Description and Operation (HVAC - Manual)

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the HVAC System. Refer to Checking Aftermarket Accessories (Checking Aftermarket Accessories).
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Verify the A/C compressor clutch turns freely and is not seized.
4. Verify that the customer is using the correct key to enable personalization and is not inadvertently activating auxiliary HVAC controls.
5. The following conditions may cause window fogging:

* Wet carpet or mats
* High humidity
* Interior water leak
* Blocked A/C evaporator drain tube
* Maximum passenger capacity
* Blocked body pressure relief valves

6. Inspect the air distribution system for causes of reduced air flow:

* Obstructed or dirty passenger compartment air filter, if equipped
* Blocked or damaged air inlet or outlet vents

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections).

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

* Blower Motor Malfunction (Blower Motor Malfunction)
* Improper Control Response (Improper Control Response)





























Low and High Side Pressure Relationship Chart





Low Side Pressure
1. 70 kPa (10 psi)
2. 138 kPa (20 psi)
3. 207 kPa (30 psi)
4. 276 kPa (40 psi)
5. 345 kPa (50 psi)
6. 414 kPa (60 psi)
7. 483 kPa (70 psi)
8. 552 kPa (80 psi)
9. 621 kPa (90 psi)
10. 690 kPa (100 psi)

High Side Pressure
1. 690 kPa (100 psi)
2. 1379 kPa (200 psi)
3. 2069 kPa (300 psi)
4. 2758 kPa (400 psi)