Heater issue 2008 XR VUE V6
 

My heater will not work all the time. Last two days it blows only cold air. Worked for a short time last week. Seems like an internal air flap is not working. Any ideas?

Can't see where you are located.

My guess is

1) heater hose or heater core mostly plugged and only a little coolant getting through. Fan blows to pull air across warm coolant inside heater core, heating the air in the process.

2) There is probably a servo controlled motor controlling a door that proportionately mixes the air described in 1 with fresh air to achieve the correct temp air. If this door gets stuck in the wrong position or the servo motor stops working correctly, you get whatever air temp that coresposnds to where the door is

3)The HVAC head unit on the fritz and and who knows what signals it is sending to the servo motor or anything else....could be interpreting the setpoint wrong....

You can check the heater core by seeing that the output hose is slightly lower in temp than the lower (input). If the top output is cold when you have a problem, the core is likely plugged.

2) is hard to hear with all the engine and cabin dinging at start up, let alone while driving. If you hear a click click click when you try to change temps, the servo motor gears may be stripped and not operating that door - but don't rip off the dash just because I GUESSED

3) seems like a GM dealership issue. What happens when you put it on AUTO control? Does it ever think it has reached the desired temp when in fact it has not?

These are plausible GUESSES based on no knowledge of vehicle, including mileage.

By the way, ever drained and swapped in new coolant? I'm gonna guess you are over 100K

I believe it's probably 2) Servo motor and stuck flap. Sometimes it will work perfect, sometimes no heat, sometimes hottest air comes out. Car only has 60k on it.

Maybe this might help...AFTER following the 2nd GM doc below (sorry)
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2008 Saturn VUE - AWD | VUE, VUE Hybrid, Captiva Sport VIN L Service Manual | HVAC | HVAC - Automatic | Repair Instructions | Document ID: 1707863
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Temperature Valve Actuator Replacement
Removal Procedure


 1. Remove the instrument panel compartment. Refer to Instrument Panel Compartment Replacement.
 2. Disconnect the electrical connector from the air temperature actuator.
 3. Remove the air temperature actuator screws from the HVAC module.
 4. Remove the air temperature actuator from the HVAC module.
Installation Procedure


 1. Align the air temperature actuator with the door shaft and rotate into position.
Notice: Refer to Fastener Notice.

 2. Install the air temperature actuator screws to the HVAC module.
Tighten
Tighten the screws to 1.5 Y (13 lb in).
 3. Connect the electrical connector to the air temperature actuator.
Important: Any time an actuator or the HVAC control module is replaced, the HVAC control module must be calibrated to ensure proper air distribution.

 4. Calibrate the actuators. Refer to Actuator Recalibration.
 5. Cycle the ignition and verify proper operation.
 6. Install the instrument panel compartment. Refer to Instrument Panel Compartment Replacement.
© 2013 General Motors. All rights reserved
___________________

I would get someone with a true scanner (not code reader) to read the B (body) codes below to ensure it is the front temp door actuator before you find yourself shotgunning parts at it. Intermittent conditions may not trigger codes. Based on every experience I've had at autozone, the can only read the Pxxxx codes.

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2008 Saturn VUE - AWD | VUE, VUE Hybrid, Captiva Sport VIN L Service Manual | HVAC | HVAC - Automatic | Diagnostic Information and Procedures | Document ID: 2207643
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DTC B0228, B0423, or B3779
Diagnostic Instructions•Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
•Review Strategy Based Diagnosis for an overview of the diagnostic approach.
•Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC DescriptorsDTC B0228 02
Recirculate Position Feedback Circuit Short to Ground

DTC B0228 04
Recirculate Position Feedback Circuit Open

DTC B0228 05
Recirculate Position Feedback Circuit Short to Battery

DTC B0228 61
Recirculate Position Circuit Actuator Stuck

DTC B0423 02
Temperature Control 2 Feedback Circuit Short to Ground

DTC B0423 04
Temperature Control 2 Feedback Circuit Open

DTC B0423 05
Temperature Control 2 Feedback Circuit Short to Battery

DTC B0423 61
Temperature Control 2 Circuit Actuator Stuck

DTC B3779 02
Air Flow Control 9 Feedback Circuit Short to Ground

DTC B3779 04
Air Flow Control 9 Feedback Circuit Open

DTC B3779 05
Air Flow Control 9 Feedback Circuit Short to Battery

DTC B3779 61
Air Flow Control 9 Circuit Actuator Stuck

Diagnostic Fault InformationCircuit
Short to Ground
Open/High Resistance
Short to Voltage
Signal Performance

Recirculation Door 5 V Reference
1
1
B0228 05, B0413 05, B3779 05
B0228 61

Recirculation Door Position Signal
B0228 02
B0228 05
B0228 05
B0228 61

Recirculation Door Controls
1
B0228 04
1
B0228 61

Recirculation Door Low Reference
1
B0228 05
1
B0228 61

Front Temperature Door 5 V Reference
1
1
B0228 05, B0413 05, B3779 05
B0423 61

Front Temperature Door Position Signal
B0413 02
B0413 05
B0413 05
B0423 61

Front Temperature Door Controls
1
B0413 04
1
B0423 61

Front Temperature Door Low Reference
1
B0413 05
1
B0423 61

Mode Door 5 V Reference
1
1
B0228 05, B0413 05, B3779 05
B3779 61

Mode Door Position Signal
B3779 02
B3779 05
B3779 05
B3779 61

Mode Door Controls
1
B3779 04
1
B3779 61

Mode Door Low Reference
1
B3779 05
1
B3779 61

1. HVAC Malfunction


Circuit/System DescriptionThe HVAC control module controls the HVAC door actuators to regulate the airflow through the HVAC system. Each actuator consists of an electric motor and a potentiometer. The module supplies a low reference and 5 V reference source voltage to the potentiometer. The HVAC control module monitors the voltage drop across the potentiometer on the door position signal circuit. When the actuator shaft rotates, the voltage on the door position signal circuit changes. The control circuits each provide either ground or B+ from the HVAC module depending on which direction the door has been requested to move, reversing the actuator motors polarity in order to change its direction.


•B0228 is for the recirculation actuator.
•B0413 is for the air temperature actuator.
•B3779 is for the mode actuator.
Conditions for Running the DTC•Ignition ON.
•The HVAC module is ON.
Conditions for Setting the DTCThe actual door position differs from the commanded door position by more than 4 counts or the HVAC control module detects the door position signal circuit is less than 3 counts or greater than 253 counts.

Action Taken When the DTC SetsThe control circuit is deactivated for the appropriate actuator.

Conditions for Clearing the DTC•The DTC becomes history when the HVAC control module no longer detects the condition that set the DTC.
•The history DTC will clear after 100 fault-free ignition cycles have occurred.
Diagnostic AidsNot all intermittent conditions will cause a DTC to be stored.

Reposition tightly pulled wire harness actuator connections to relieve taught wires at connectors, and apply dielectric grease to actuator terminals to eliminate/minimize intermittent conditions.

Wiggle the harness near the connector to inspect terminal joints for loose connections.

Reference InformationSchematic Reference
HVAC Schematics

Connector End View Reference
Component Connector End Views

Description and Operation
Air Delivery Description and Operation

Air Temperature Description and Operation

Electrical Information Reference
•Circuit Testing
•Connector Repairs
•Testing for Intermittent Conditions and Poor Connections
•Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information

Circuit/System Testing 1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate actuator.
 2. Test for less than 10 Ω between the low reference circuit terminal 1 and ground.
⇒ If 10 Ω or greater
2.1. Ignition OFF, disconnect the harness connector at the K33 HVAC control module.
2.2. Test for less than 2 Ω in the low reference circuit end to end.
⇒ If 2 Ω or greater, repair the open/high resistance in the circuit.
⇒ If less than 2 Ω, replace the K33 HVAC control module.
⇓ If less than 10 Ω
 3. Ignition ON.
 4. Test for 4.8–5.2 V between the 5 V reference circuit terminal 3 and ground.
⇒ If less than 4.8 V
4.1. Ignition OFF, disconnect the harness connector at the K33 HVAC control module.
4.2. Test for infinite resistance between the 5 V reference circuit and ground.
⇒ If less than infinite resistance, repair the short to ground on the circuit.
⇓ If infinite resistance
4.3. Test for less than 2 Ω in the 5 V reference circuit end to end.
⇒ If 2 Ω or greater, repair the open/high resistance in the circuit.
⇒ If less than 2 Ω, replace the K33 HVAC control module.
⇒ If greater than 5.2 V
4.1. Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON.
4.2. Test for less than 1 V between the 5 V reference circuit and ground.
⇒ If 1 V or greater, repair the short to voltage on the circuit.
⇒ If less than 1 V, replace the K33 HVAC control module.
⇓ If between 4.8–5.2 V
 5. Verify the appropriate scan tool Door Actual parameter is greater than 250 counts
⇒ If less than 250 counts
5.1. Ignition OFF, disconnect the harness connector at the K33 HVAC control module.
5.2. Test for infinite resistance between the signal circuit and ground.
⇒ If less than infinite resistance, repair the short to ground on the circuit.
⇒ If infinite resistance, replace the K33 HVAC control module.
⇓ If greater than 250 counts
 6. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1.
 7. Verify the appropriate scan tool Door Actual parameter is less than 5 counts
⇒ If greater than 5 counts
7.1. Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON.
7.2. Test for less than 1 V between the signal circuit and ground.
⇒ If 1 V or greater, repair the short to voltage on the circuit.
⇓ If less than 1 V
7.3. Test for less than 2 Ω in the signal circuit end to end.
⇒ If 2 Ω or greater, repair the open/high resistance in the circuit.
⇒ If less than 2 Ω, replace the K33 HVAC control module.
⇓ If less than 5 counts
 8. Test for less than 1 V between each control circuit terminal listed below and ground.
◦Control Circuit - terminal 4
◦Control Circuit - terminal 5
⇒ If 1 V or greater
Repair the short to voltage on the circuit.

⇓ If less than 1 V
 9. Ignition OFF.
10. Test for infinite resistance between each control circuit terminal listed below and ground.
◦Control Circuit - terminal 4
◦Control Circuit - terminal 5
⇒ If less than infinite resistance
Repair the short to ground on the circuit.

⇓ If infinite resistance
11. Test for less than 2 Ω in each control circuit listed below end to end.
◦Control Circuit - terminal 4
◦Control Circuit - terminal 5
⇒ If 2 Ω or greater
Repair the open/high resistance in the circuit.

⇓ If less than 2 Ω
12. Test or replace the actuator.
13. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
14. Verify the DTC does not set.
⇒ If the DTC sets
Replace the K33 HVAC Control Module.

⇓ If the DTC does not set
15. All OK
Repair Instructions Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•Air Inlet Valve Actuator Replacement
•Mode Valve Actuator Replacement
•Temperature Valve Actuator Replacement
•Control Module References for HVAC control module replacement, setup, and programming
© 2013 General Motors. All rights reserved

Here's the HVAC schematic and a picture of the HVAC head and associated removal and reassembly of the temperature valve actuator

Please come back and tell us the resolution.

Excellent
 

Thanks so much for the time and effort on this!

It's all about helping each other out around here....

That and a few cheap shots here and there

Please stop back and let us know what the resolution was/is.

And as soon as you START to develop a shift flare from 3rd to 4th, 5th to 6th or you START to lose reverse, SELL IT on the spot without getting it diagnosed. The 6T70 trannys (originals) are ticking timebombs, and unless they've increased the warranty on the 3,5,R Waveplate defect, you're basically looking at a massive labor bill and smaller parts bill on the order of $2500 to fix the trans out of pocket.

There is a TSB out for the problem. The question is how they will handle it.

Mine went at 93K on a 100K ext warranty.

I've also read about these vehicles developing a front brake issue where the calipers sneak in and start grabbing the rotors on their own, creating tremendous amounts of heat, warped rotors, scorched pads, and , most importantly, unsafe driving conditions. Please do follow up on this one as I don't know if it is a design flaw or just massive owner non-maintenance/ignorance that brought this one to the forefront.

My transmission went out at 52K cost me $3200, sent several complaint letters to GM they reimbursed me about 5 months later. The exact scenario happened as you described, failed in the middle of a busy intersection. Now besides the heater issue my engine mounts are failing.

Happy Holidays!

mounts are kind of maintenance items these days (consumables) --- At leat the torque axis mounts as they take the most beating, keeping the engine from rotating in the engine bay. Are you making that diag based on visual inspection, more vibration in the cabin....?

Sorry to hear about your tranny. 52K? Cheeez wizzzzz. I'm surprised they covered any of it let alone all of it.

They must be getting bombarded with angry letters. I'll bet you mentioned the "middle of the intersection " timing -- which they read as "safety issue" which leads to "recall" and they sure don't want that.

I guess the "persistent squeaky wheel screaming safety" does get heard once in a while.

Good for you on the tranny. Not that it crapped out -- that you got reimbursed.

My prediction is that the will recall them when forced to (after people die because of it), and then will tell you to take it to a GM approved tranny shop and get it fixed. Which is exactly what they will do anyway.....

HVAC actuator module
 

By the look of this HVAC picture, this is what I believe is causing my cold air only, coming only out at floor issue..Worked when we purchased ...now there's this flapping noise from behind-above center console-dash...Blows strong, but only cold at floor...little out upper vents..just started getting MIL on dash....so...Only had a 30 day warranty, however we purchased all inclusive warranty for the engine, trans etc..for another 5 years...has 47K now....crossing my fingers..and terribly disappointed ..really a very well taken care of vehicle...and I wanted one because of their reliability ratings....
Mistake ?