Hi,
I have read several threads about the HVAC codes for the dual climate control system. Since I bought my 2004 Convertible a few months ago I keep getting the "0363 H" code every few hours of driving (not necessarily correlated to ignition cycles.) That is the only code that comes up. If I check the codes quick enough when the temp goes high, I have seen "0363 C," but usually just an "H." (OK, where is that wood that I need to knock on!)

From reading the threads about the actuators, it seems that Chevy changed something on the climate control actuating system about 2001 to an automatic resetting actuator.

In my case, the temp will go from where I have it set (about 72-73) to 87 degrees. I just turned the temp **** back to 73 and so far all is well. It will work fine for a few hours of driving and the same thing will occur. I reset the code when I have the chance.

Question, do I need to change or reindex the driver's actuator like I have read about for the 97-2000 Corvettes, or should I just enjoy the car and not worry about it?

I ask because I do not want to be on a long trip and have the AC go out when I could have fixed it at home.

Dan

 

Looks like a problem with the Left air temp actuator. Since it is high voltage error it indicates the door is opening too far. The control unit then sends a default value. NOT LIKELY TO CAUSE A FAILURE IN THE SYSTEM but should be resolved.
Service Information Circuit Description

The HVAC control module commands the left air temperature actuator to move by controlling the voltage supplied on the control circuit. A low voltage of 0 volts moves door toward full cold. A voltage of 2.5 volts stops the door. A high voltage of 5 volts moves the door toward full hot. The HVAC control module determines the current position of the actuator by monitoring the voltage on the signal circuit. The feedback potentiometer is a function of the motor position. A high voltage of 4-5 volts indicates full cold door position. A low voltage of less than 1 volt indicates full hot door position. The HVAC control module controls the left air temperature actuator door positions in order to maintain the selected air temperature.
Conditions for Running the DTC

The ignition is turned ON.
Conditions for Setting the DTC

The HVAC control module detects the signal circuit is greater than 250 counts (4.90 V).
Action Taken When the DTC Sets

A default value will be used for the sensor data by the HVAC control module in an attempt to maintain the air temperature selected by the driver. This default value will be displayed on the scan tool.
Conditions for Clearing the DTC

• The DTC will become history if the HVAC control module no longer detects a failure.
• The history DTC will clear after 100 fault free ignition cycles.
• The DTC can be cleared with a scan tool.

Diagnostic Aids

A disconnected or broken door may also set this DTC by allowing the left air temperature actuator to travel to its internal stops, an overtravel condition. If condition not present, refer to Testing for Intermittent and Poor Connections in Wiring Systems.
Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. Tests for a default setting viewed by the scan tool.
2. Tests for the proper operation of the circuit in the high voltage range.
3. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
4. Tests for a short to ground in the 5 volt reference circuit.

Step
Action
Values
Yes
No
Schematic Reference: HVAC Schematics
1
Did you perform the HVAC Diagnostic System Check?
--
Go to Step 2
Go to Diagnostic System Check - HVAC Systems - Automatic
2

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, observe the LH Mix Mtr Position Feedback parameter in the Heating and Air Conditioning data list.

Does the scan tool indicate that the LH Mix Mtr Position Feedback parameter is within the specified range?
5-250 counts
Go to Step 3
Go to Step 4
3
Place the air temperature switch from the warmest position to the coldest position.
Does the scan tool indicate that the value of the LH Mix Mtr Position Feedback parameter remains near the specified value?
127 counts
Go to Step 4
Go to Diagnostic Aids
4

1. Turn OFF the ignition.
2. Disconnect the left air temperature actuator.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage from the signal circuit of the left air temperature actuator to a good ground.

Is the voltage greater then the specified value?
4.90 V
Go to Step 5
Go to Step 9
5

1. Turn OFF the ignition
2. Connect a 3 amp fused jumper wire between the signal circuit of the left air temperature actuator and the low reference circuit of the left air temperature actuator.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage from the jumper wire to a good ground.

Is the voltage less then the specified value?
0.09 V
Go to Step 6
Go to Step 10
6

1. Turn OFF the ignition.
2. Disconnect the fused jumper wire.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage from the 5 volt reference circuit at the left air temperature actuator to a good ground.

Is the voltage greater then the specified value?
4.90 V
Go to Step 8
Go to Step 7
7
Test the 5 volt reference circuit of the left air temperature actuator for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 16
Go to Step 13
8
Test the 5 volt reference circuit of the left air temperature actuator for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 16
Go to Step 12
9
Test the signal circuit of the left air temperature actuator for a short to ground, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 16
Go to Step 13
10
Test the signal circuit of the left air temperature actuator for a short to voltage, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 16
Go to Step 11
11
Test the low reference circuit of the left air temperature actuator for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 16
Go to Step 13
12
Inspect for poor connections at the harness connector of the left air temperature actuator. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 16
Go to Step 14
13
Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 16
Go to Step 15
14
Important

Perform the recalibration procedure for the left air temperature actuator.


Replace the left air temperature actuator. Refer to Air Temperature Actuator Replacement - Left .
Did you complete the replacement?
--
Go to Step 16
--
15
Important

Perform the recalibration procedure for the HVAC control module.


Replace the HVAC control module. Refer to HVAC Control Module Replacement .
Did you complete the replacement?
--
Go to Step 16
--
16

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

 

Interesting, after posting my above request about HVAC 0363, this afternoon I got a 0361 H (short to ground.) So it looks like I have a loose or broken connection in the actuator circuit.

I don't have a scan tool. I do have the 2004 Corvette Maintenance manual. (I did not say that it is easy to use and find items. The table of contents and the index could be better.)

However, because this is an intermittant problem, my thoughts are poor electrical connections at either/or
A. left actuator
B. HVAC module
c. Ground G202 and SP 202 in the right door pillar

When the outside temperature comes below 104F I am going to checkout these items in reverse order.

First question in what will probably be a string of several:

How do you pull off the long trim piece (about 30-36"long) along side the passenger seat that covers the top of the carpet and sits under the door when closed? I assume that it justs pulls out, but some knowledge will be cheaper than brute force.

This is for the ground G202.

 

Yup you just pull up on it with some force, start with popping up the back end then sliding it to the rear but be careful not to pull real hard or you'll chance breaking the tap on the front