enigma94

Well, as im sure some of you are aware of the issue a lot of us have with the mode setting not actually switching modes ( I.E only feet, front air vents, both ect) I had this issue at the begining of the summer and after removing everything on that side of the car(fender/battery ect) I found the plastic vacuum hose that had been eaten away by a previous old and corroded battery. I replace the whole hose, checked all the other ones, and even wrapped them all in electrical tap as to try to insulate them from getting dry and cracking again.

Well today I get in the car and fire up the a/c and the issue is back, but it seems to only be intermittent at first and now its just stuck blowing out all the vents AGAIN. I just got done pulling everything out again and found a couple possible pinched lines but replaced them and the issue is STILL there and im pretty much stumped.

My battery died about 2 days ago, just out of nowhere, and at that same time my key fob stopped responding completely ( the number 1 keyfob the second back up one is working) didnt have any signs of an issue with the battery voltage or anything like that, parked the car for 2 hours came back and it was dead as a rock. Now the reason why I bring this up is about a week prior tho all of this I used the cigarette lighter with a pretty unsafe power converter and im wondering if somehow I fried something in the electrical system and its leading to all of these other issues. I check all the fuses under to hood by the battery and they all looked good, so im really just stumped as to what could have caused all of these issues just out of nowhere.

If any of you have experienced this or have any idea as to what it could be or what to check to narrow it down I'd really appriciate it, as I do not have the cash to take the car to the dealership to have them look at it right now and its 110 in the day here and the car is my daily driver.

TIA!

Fastguy

When I unbolted the bottom of the fender, not only were the lines cracked but I vaguely remember a little plastic cylinder thing that was broken as well.

enigma94

See, having changed the lines before im pretty familiar with where they all go and such, and I checked them all over again and there is no issues with any of them, the connectors they go into or the box, which is why im so stumped as to what it could be. Unless it was the line from the back of the IM which is pretty much impossible to see without taking the whole thing off I really have no idea what could be causing this.

I just pulled the codes and here is what came out

A0-LDCM :

B2282-H
B2284-H
U1064-H
U1096-H

A1-RDCM:

B2283-H
B2285-H
U1064-H
U1096-H

Ive found that these are the B codes but I cant find anything on those U codes..
B2282 Battery #1 Circuit
B2283 Battery #1 Circuit
B2284 Battery #2 Circuit
B2285 Battery #2 Circuit

and I'm not even sure what that means? and how do i clear them?

Mxzx

A0-LDCM : Left Door Control Module

B2282-H Battery #1 Fault
B2284-H Battery #2 Fault
U1064-H Loss of Comm w/ BCM
U1096-H Loss of Comm w/ IPC

A1-RDCM: Right Door Control Module

B2283-H Battery #1 Fault
B2285-H Battery #2 Fault
U1064-H same as above
U1096-H same as above

dgrant3830

Push and briefly hold the reset button while the code is displayed. That will clear it. Have you checked the fuses in the passenger footwell? There is a resync procedure for the HVAC controller, but I don't have a clue what it is.

Jacks2002

On a side note, if you take your car to the dealer to have the AC problem fixed, what kind of charge can you expect? Mine is toast as well. (Old battery leak)

enigma94

I took it in when the issue first came up and they couldnt tell me how much it would be but the guy told me it probably wouldnt be under 500 and guessed somewhere in the range of 7-900. It honestly isnt that hard to fix if you can find the broken line, it took me about 3 hours. I actually took pics and wanted to do a write up on it but havnt had to chance to sort the pics and write it all down.

I have not checked the fused in the passenger side footwell, I will check those out, and since I cant seem to find a broken line anywhere and had all these battery issues before hand maybe a reset is all it needs, if anybody could point me in the right direction as to how to do that i'd appriciate it!

bestvettever

Hi, when all vents are open and uncontrolled by the Control Head,(CH), it is usually a vacuum issue, either a broken or disconnected line below the battery box or a disconnected line from the 90degree nipple on the back of the intake manifold. Other possibilities are a bad CH, or a disconnected line at the vacuum block,(inside the car behind the glove box), there is a purple line that comes from the vacuum block that connects to the line coming in from the tank in the engine bay,(the connection is in the car behind the glove box), or a cracked vacuum tank, in the engine bay right side under the battery box. The simplest way to get an idea as to which it is is to disconnect the line under the battery that comes from the intake manifold and with the car running put your finger over it and see if there is vacuum, a vacuum gage works better, but your finger should be able to feel it, if no vacuum is there than your problem is in the line going to the im or the connection at the im. If there is vacuum, than reconnect it and disconnect the line coming from the check valve that goes into the car and feel for vacuum there, if none exists, the problem is either the check valve, or the tank, or a break in between, if there is vacuum move on into the car and check for the presence of vacuum at the vacuum block, and control head, and then the vacuum actuator at the unit itself. Somewhere down the line you will find the answer. If vacuum exists all the way to the actuator itself, then it is obviously either the bad actuator, or the mode door may be stuck, out of line or broken. Below is a complete description of how the system works, a bit of troubleshooting and deductive reasoning will get you back running again..
Good Luck
+++++++++++++++++++++++++++++++++++++
Air Delivery Description and Operation
The air delivery description and operation are divided into five areas:

HVAC Control Components
Air Speed
Air Delivery
Recirculation Operation
Automatic Operation
HVAC Control Components
HVAC Control Module
The HVAC control module is a class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive voltage circuit provides power that the control module uses for keep alive memory (KAM). If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from KAM. The ignition 3 voltage circuit provides a device on signal. Three integrated potentiometers control mode and air temperature door positions and blower motor speed. The control assembly communicates the mode door position to the vacuum control assembly through 5 solenoid control circuits. The control module supports the following features:

Feature
Availability

Afterblow
No

Purge
No

Personalization
No

Actuator Calibration
Yes


Air Speed
The blower motor circulates air through the vehicle's interior. The vehicle operator determines the blower motor's speed by pressing the blower motor switch manually or by using the automatic mode. The blower motor will only operate if the blower motor switch is in any position other than OFF, as long as the ignition switch is in the RUN position. The blower motor and mode switches are located within the HVAC control module.

Power is provided to the blower motor from the blower motor control processor through the blower motor supply voltage circuit. The blower motor control processor receives power from the instrument panel fuse block through the battery positive voltage circuit. Ground is provided by the blower motor control processor, ground circuit and splice pack.

The HVAC control module receives power from the instrument panel fuse block on the ignition 3 voltage circuit along with the battery positive voltage circuit. The module is grounded by the ground circuits and splice pack. The HVAC control module communicates directly to the powertrain control module (PCM) on the class 2 serial data circuit through the star connector.

When any blower speed is selected, whether manual or automatic, the blower motor control processor will control blower motor speeds based on voltage signals from the HVAC control module. A 5-volt signal is sent from the blower motor control processor to the HVAC control module on the blower motor speed control circuit. When the driver manually selects a blower speed or the automatic HVAC system determines a needed speed, the HVAC control module will provide a pulse width modulated (PWM) ground. The remaining voltage at the blower motor control processor is used to provide a blower motor speed signal. A 12-volt signal is sent to the blower motor from the blower motor control processor on the blower motor supply voltage circuit. The blower motor control processor varies the ground on the blower motor control circuit internally with a separate PWM signal. An open circuit, short to ground or short to battery on the blower motor speed control circuit will disrupt the PWM signal and cause the blower motor to not operate. In automatic operation, the HVAC control module will determine what blower speed is necessary in order to achieve or maintain a desired temperature.

When in manual mode, the driver can change the blower speed by pressing the blower motor switch. If the driver presses the blower motor switch once, the blower speed will increase/decrease 1 level. Holding the blower motor switch down will increase/decrease the blower speed to the maximum/minimum speed.

Off
Press the OFF switch to turn OFF the HVAC system. When the vehicle is moving, air flowing over the vehicle increases the air pressure just ahead of the windshield. This forces air into the HVAC air inlet and out through any desired mode setting. The HVAC control module attempts to match the inside air temperature and HVAC control module selected temperatures. Driver set temperature and passenger temperature offset can be adjusted. Since the A/C compressor is not running, the incoming air may be warmed but not cooled.

Air Delivery
When the mode switch is pressed, a signal is sent from the HVAC control module to the vacuum control assembly. The HVAC control module will provide ground for the necessary mode actuator solenoid, connecting the desired mode actuator to vacuum. The instrument panel fuse block provides power to the vacuum control assembly through the ignition 3 voltage circuit. Ground is provided by the HVAC control module.

Mode Switch
Use the MODE switch in order to change the air delivery mode in the vehicle. Selection of the MODE switch when in AUTO mode will lock in the air flow mode that AUTO was controlling. The system will stay in that mode until the MODE or AUTO switch is pressed. Pressing the MODE button also activates the digital display for the mode selected. If an airflow mode is currently displayed, pressing the MODE button selects the next air flow mode. The air flow direction will sequence through the following modes:

PANEL
BI-LEVEL
DEFOG
FLOOR
Defog
When the driver selects the MIX-BLEND mode, air delivery is divided between the floor and windshield outlets. The HVAC control module ground the mix-blend mode valve solenoid control circuit. When the solenoid is grounded, vacuum is applied to the mode actuator through the Blue vacuum line, and to the defrost actuator through the Red and the Yellow vacuum lines. The mode actuator will retract, closing the vent door. Applying vacuum to both sides of the defroster actuator will hold the defroster door stationary in the half open position. The heater door will also be held stationary in the half open position through mechanical linkage.

Floor
When the driver selects the FLOOR mode, air is delivered through the floor outlets with some toward the windshield and side vents. The HVAC control module grounds both the lower mode valve solenoid control and the mix-blend mode valve solenoid control circuit. When the solenoids are grounded, vacuum is applied to the mode actuator through the Blue vacuum line, and to the defrost actuator through the Red vacuum line. The mode actuator will retract, closing the vent door. The defroster actuator will retract, closing the defroster door and open the heater door through mechanical linkage.

Bi-Level
When the driver selects the BI-LEVEL mode, cool air is delivered through the instrument panel outlets while warm air is delivered through the floor outlets. The HVAC control module grounds the lower mode valve solenoid control circuit. When the solenoid is grounded, vacuum is applied to the mode actuator through the Brown and the Blue vacuum lines, and to the defrost actuator through the Red vacuum line. Applying vacuum to both sides of the mode actuator will hold the vent door stationary in the half open position. The defroster actuator will retract, closing the defroster door and open the heater door through mechanical linkage.

Panel
When the driver selects the panel mode, air is delivered through the instrument panel outlets and a small amount is delivered to the floor. The HVAC control module grounds the lower mode valve solenoid control and defrost mode valve solenoid control circuit. When the solenoids are grounded, vacuum is applied to the mode actuator through the Brown vacuum line, and to the defrost actuator through the Red vacuum line. The mode actuator will retract, opening the panel door. The defroster actuator will retract, closing the defroster door and open the heater door through mechanical linkage.

Front Defrost
If the HVAC system is in front defrost mode when you turn the vehicle OFF, the HVAC system will restart in front defrost unless the engine is OFF longer than 40 minutes. If the engine is OFF longer than 40 minutes, the system will restart in the previous operating mode set prior to using front defrost, with outside air being drawn into the vehicle.

The front defrost mode is the only setting that is not controlled by the automatic HVAC system. When FRONT DEFROST is selected, the A/C compressor is activated and outside air is brought into the vehicle. The blower motor will be activated and air will be directed toward the windshield with a small amount of air toward the side window outlets. Pressing the AUTO or OFF button will turn OFF front defrost mode. Pressing the FRONT DEFROST button will return the HVAC system to the last operating mode. Recirculation mode is not available in front defrost. The rear window defogger does not affect the HVAC system at all.

The HVAC control module grounds the upper mode valve solenoid control and the mix-blend mode valve solenoid control circuits. When the solenoids are grounded, vacuum is applied to the mode actuator through the Blue vacuum line and to the defrost actuator through the Yellow vacuum line.

Recirculation Operation
Outside Air
When the OUTSIDE AIR switch is pressed, outside air is brought into the vehicle. This mode has no effect on the system when FRONT DEFROST mode is selected. OUTSIDE AIR and RECIRCULATION are separate modes and are not available together. When OUTSIDE AIR is selected, when in automatic mode, the HVAC system will stay in this mode until AUTO is pressed again.

Recirculation
When the recirculation is requested, whether manual or automatic, a solenoid inside the vacuum control assembly connects the recirculation actuator to the vacuum source. Power is provided to the recirculation solenoid by the ignition 3 voltage circuit. Ground is provided by the recirculation valve solenoid control circuit and HVAC control module. When the solenoid is grounded, vacuum is supplied to the recirculation actuator. The recirculation actuator retracts, closing the recirculation door. This draws air from inside the vehicle instead of fresh air from the outside.

Recirculation can be used in both automatic and manual operation. The only time recirculation is not available is when FRONT DEFROST or MIX-BLEND is selected. The RECIRC LED will flash three times to alert the driver that recirculation mode is not available. When in automatic mode, recirculation will stay ON until either the vehicle operator selects OUTSIDE AIR or the automatic system has cooled the vehicle sufficiently.

Automatic Operation
Automatic
The automatic HVAC system will warm up/cool down and maintain the interior temperature of the vehicle by controlling the A/C compressor clutch, blower motor, air temperature, mode and recirculation actuators to achieve the desired temperature. For fully automatic operation, both the blower and mode switches must be in the AUTO position. Blower speeds will change automatically based on inputs to the HVAC control module. The HVAC control module will always come back to the last settings after an ignition cycle or, if equipped, to the last settings of the driver by pressing the UNLOCK button on the remote keyless entry fob and placing the ignition in RUN.

In cold temperatures, the automatic HVAC system will provide heat in the most efficient manner. To warm the interior quickly, maximum heat is used where the blower is at maximum speed, floor mode, air temperature is in full hot and outside air is being drawn in. The vehicle operator can select the extreme warm setting, but the system will not warm the vehicle any faster. Once the desired temperature is reached, the blower motor, mode, recirculation and temperature will be adjusted automatically by the HVAC control module.

In warm temperatures, the automatic HVAC system will provide A/C in the most efficient manner. To cool the interior quickly, full cold is used where the blower is at maximum speed, air temperature actuator is in full cold and the recirculation actuator is drawing air from inside the vehicle. The vehicle operator can select the extreme cool setting, but the system will not cool the vehicle any faster. Once the desired temperature is reached, the blower motor, mode, recirculation and temperature will be adjusted automatically by the HVAC control module.
+++++++++++++++++++++++++++++++++++++

Below is a good link to view pictures of these various areas. Bill Curlees post #8 is invaluable to give you a very good idea of what these things look like.
http://forums.corvetteforum.com/c5-t...nge-vents.html

enigma94

Thank you for the informative post! I used bills post when I first repaired the issue a couple montsh ago, but after reading it again, I am deducing that since I do not have a HVAC code that its not an actual mechanical(or part a part going bad/electrical clip) issue but has to be a vacuum issue, would this be correct or could it still be a bad part somewhere under the dash and its just not throwing a code?

enigma94

Scratch that last post, I was driving today with the air on full blast ( and still sweating my *** off) and the check engine light came on so I went to a Autozone to have them check ti with their scanner and it came back with a P0410 AIR System code, which on the scanner reads:

" BB secondary Air Injection system fault
Explanation: BB the secondary Air Injection System is monitored for faults probable cause:
BB1: Circuit relay fedective or fuse open
BB2: Check connector and wireing
BB3: Air pump defective or hoses blocked"

So, its saying there is something wrong with the "secondary air injection system" is there anything even like this in the HVAC system if so where would I go about finding it it? I am going to be pulling the car apart tomorrow to find this issue, I just am wonder if im going to end up having to remove the dash and all of that to get to the unit behind the glove box or not. If anybody knows where this secondary system is or if it even exists(under a different name maybe?) it'd help a lot when i tear it all down tomorrow!

byronhunter

Bestvettever posted you a link in post #8. The vacuum problem also affects the AIR problem you're having. Go read it again, Bill Curlee has some of your problem well covered!

enigma94

Hmm, maybe I miss read it the couple of times I looked over it. Im thinking the secondary Air thing the code is talking about is one of those 2 Diaphram/ball looking things in the pictures he posted. I just really, reaaaaly hope I dont have to take the dash out

byronhunter

enigma94, it's not Air, it's AIR, AIR INJECTION REACTION. System that pumps fresh air into the exhaust manifolds.

bestvettever

Hi, byron, you can lead a horse to water. Enigma, at this point there is no reason to think that you have to take the dash apart. The fact that you got the P0410 is most likely telling you that a vacuum problem exists before the vacuum is ever reaching the inside of the car. The AIR solenoid valve is located in the same area as the other AC vacuum lines in the pass side fender well area. Look closely at the picture with the tank, and lines, in post #8. . You will see the line designated "Solenoid Above PCM", that feeds the AIR solenoid valve. It is experiencing a no vacuum condition. That is something in common with your AC system, also experiencing a no vacuum condition. You are going to have to bite the bullet and get a look at the 90degree nipple on the back of the manifold and the other lines mentioned in my previous post. Your problem is in them somewhere. Do what was suggested and test for vacuum in those lines and you will find the problem.
Good Luck

lucky131969

I'm betting it's a fendective relay circuit......

bestvettever

Is that the same as the reflective delay circuit???
Semper FI

Speedball

I spoke with someone who has a huge inventory of C4 parts and who said that the HVAC Solenoid assembly is failing and replacing the solenoids is what's necessary....I mentioned that when the A/c-Heater recycles through aqs though it's insane, that a white mist shows up on the lower part of the exterior winsdshield...he said that's the heater core that's going south and needs to be rebuilt... I've got 83,000 miles on it and it's gorgeous and goes like hell, but I feel like once more GM has left us with hind teat and no solutions. Except to find someone who rebuilds both the HVAC Solenoid Assembly...the man with the parts said, "I've got the assemblies but they have the old prone to fail pieces that you need to replace anyway, just rebuild yours".....WHO REBUILDS THESE IN LOS ANGELES???

redzg

Hunh?
You noticed this was a nine year old thread? Are you having the same problem as the OP, in that you've fixed the vacuum line before and are now having the issue recur?

Ruouthere

Just had my hose(s) replaced today due to a previous leaking battery, with labor around $300. They also found the acid dripped onto the frame which has stripped the factory creating leaving bare and rusty metal surfaces. Hope that helps.

silver50

Re post #8 above, there’s a detailed HVAC functionality description that sounds accurate.

Here’s an excerpt (I’d like to be certain about something relating to this).

This is for when your HVAC air flow is set to DEFOG (not DEFROST) so air to go to feet and screen
When the solenoid is grounded, vacuum is applied to the mode actuator through the Blue vacuum line, and to the defrost actuator through the Red and the Yellow vacuum lines. The mode actuator will retract, closing the vent door. Applying vacuum to both sides of the defroster actuator will hold the defroster door stationary in the half open position

I’ve seen the vacuum actuators referred to as “3 position” but is this as described above (vacuum applied either side to gain a central position) or should the actuator rest (for example engine off) at a central position?

I suspect the above description is wrong but I have gathered this week that C5’s have two different schematics relating to the vacuum solenoid getting its signals.

My car’s RH actuator certainly doesn’t rest in the centre. It stays where it was pulled to last. However it operates ok either way ok under vacuum. Maybe through age my diaphragm isn’t springing it back to central but that seems odd.

I like to clear these things up because forum members would see the above as gospel when searching etc.