HELP! My 97 blowing hot and cold at once!

[Deke]

Thanks everyone for the welcome. So my first problem is this new 97 vette blows cold air on the passenger but hot air from the center vent and the driver, read the owner's manual and am wondering if I missed something. Any suggestions. Thanks- Dave

 

[XLR8]

Deke, I'm going to break away this latest post to a separate thread in the C5 forum because replies would be limited based on its presence here in the New Members Forum.

Here we go...

I had a similar problem with my 98 years ago, which turned out to be a broken actuator.

http://www.corvetteactioncenter.com/forums/c5-technical-performance/94652-ac-blowing-cold-hot.html

Yours may not be the same problem but it sounds exactly like mine as described in the thread linked above.

 

[Hib Halverson]

When you say "new 97 Vette" we'll assume that you just purchased a used 97.

If the hvac blows hot from two outlets and cold from the third, I'd take the car back to the dealer which sold it to you and ask them to repair the hvac such that it works properly.

 

[XLR8]

When you say "new 97 Vette" we'll assume that you just purchased a used 97.

If the hvac blows hot from two outlets and cold from the third, I'd take the car back to the dealer which sold it to you and ask them to repair the hvac such that it works properly.

He did just purchase the "used" 97, Hib. He stated as much in his introduction thread here:

http://www.corvetteactioncenter.com/forums/new-member-introductions/129022-intro.html#post1086956

He then asked for input on an HVAC issue he's having so I moved the post into its own thread because it's been my experience that fewer members read the introduction threads than the tech threads. Actually, you helped prove the point.

Whether he bought from a dealer or private owner, I can't say. I only know he asked for suggestions.

Jane Ann

 

[Deke]

Hot and cold and more

Thanks for your help. Scrolled through who knows how many posts and threads, finally stumbled on one that said remove fuse #27 under the passenger floor board, disconnect battery, wait 3 minutes, then plug everything back in. Surprise the A/C works just like it should. Now the check engine light is on complaining about some kind of traction control and engine power reduction. This car is driving me crazy. Oh well, what else is retirement for if not to go back to college and take a degree in computer engineering.




QUOTE=XLR8;1087586]He did just purchase the "used" 97, Hib. He stated as much in his introduction thread here:

http://www.corvetteactioncenter.com/forums/new-member-introductions/129022-intro.html#post1086956

He then asked for input on an HVAC issue he's having so I moved the post into its own thread because it's been my experience that fewer members read the introduction threads than the tech threads. Actually, you helped prove the point.

Whether he bought from a dealer or private owner, I can't say. I only know he asked for suggestions.

Jane Ann[/QUOTE]

 

[jrose7004]

I had a 98 coupe that used to do that when it would need a freon charge.

 

[XLR8]

I'm glad it was a simple fix. If memory serves, I think the steps you took may have forced the actuator to cycle and basically reset itself. I-f memory serves, that is.

In my case the gear was cracked and resetting didn't work.

On to the next issue!

 

[Hib Halverson]

Thanks for your help. Scrolled through who knows how many posts and threads, finally stumbled on one that said remove fuse #27 under the passenger floor board, disconnect battery, wait 3 minutes, then plug everything back in. Surprise the A/C works just like it should. Now the check engine light is on complaining about some kind of traction control and engine power reduction. This car is driving me crazy.

(snip)

The way the previous post was phrased has me thinking you have never done any engine controls diagnostics before.

Are you intent upon trying to repair the car yourself?

 

[Deke]

(snip)

The way the previous post was phrased has me thinking you have never done any engine controls diagnostics before.

Are you intent upon trying to repair the car yourself?[/QUOTE


Well, yes and no. Eager to learn but smart enough(I hope) to know where eagerness ends and the bottom end of knowledge begins. That's when CAC enters the room. The #27 fuse is a peerfect example, I wouldn't have thought of that in a million years. I'm not about to start randomly pushing buttons on this car without knowing what to expect. This is a learning project in progress and I cannot thank all of you enough for your advise and knowledge.

 

[Curious George]

I had a similar issue with my 1999 convertible. I replaced the driver side actuator door based on codes from the DIC. The OE actuator gear did what they all do... the plastic gear split for the metal center piece / hub. After this was complete, I still had warmer air from the center and driver side vents, but cool air from the two passenger side vents.

I topped off the refrigerant charge (R134a) and all vent temps were back to normal. This was back in July of this year. I can begin to feel a temperature variance again between the center / driver side vents compared to the passenger side vents. The compressor has a very slow leak from the front shaft seal. After the new year I plan on fixing it long before the spring / summer get here.

CG

 

[Hib Halverson]

In re-reading your posts, my understanding is that your problems with hvac went away when you pulled then replaced that fuse.

Is your hvac still working properly?

You mentioned the service engine light was on but you also mentioned a problem with traction control. Are there any other service lights on besides the "check engine" light? Is the "reduced engine power" message still showing on the IP display?

Lastly, do you know what code(s) are set in the ECM or, maybe, the EBTCM? If you don't, either read your factory service manuals or search here on CAC for the procedure used with C5s to get the car's on-board DTC display mode to give you that information. When you have the fault code data, post the codes here.

Once we have that info you'll get a number of replies with suggestions for fixes.

 

[Hib Halverson]

Lists you find on-line may or may not be correct. The only list of DTCs you can be sure is right will be in the 97 factory manual.

What codes did you find when you read all the modules?

 

[Junkman2008]

Allow me to post a correction in the fix for recalibrating the HVAC. What the OP posted as the fix is slightly off, although it worked for him. The correct procedure is:

Re-Calibrating Actuators

Use the following steps to perform the calibration update:

1. Turn OFF the ignition.

2. Remove the battery positive voltage circuit fuse of the HVAC Control Module (fuse 27, located in the passenger's side floorboard by the BCM).

3. Wait 60 seconds.

Important
The module memory will not clear if the battery positive voltage circuit fuse is installed in less than 60 seconds.

4. Install the fuse.


There is no need to disconnect the battery whatsoever.

 

[Bill Curlee]

DTCs

Learn to read and post your DTCs!

READING YOUR Engine Diagnostic Codes (DTCs)
The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open etc…)
3) Press and hold OPTIONS
4) While holding OPTIONS, press FUEL four times within a 10-second period.

Initially, on-board diagnostics go into an Automatic Mode which shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each. ( i.e. PCM = 4 codes)
If none are present in a given module, you will see No More Codes on the display.
There are two kinds of diagnostic codes, Current and History designated with a letter suffix, C or ;H. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes.
More likely it's an indication of an intermittent malfunction.
Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.
Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present;
press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET
To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles.
Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

Here is very good site of DTC definitions:


http://www.gearchatter.com


Make sure to include the H or C suffix!!

 

[Junkman2008]

Wassup Bill You venturing away from CF these days?

 

[Bill Curlee]

LMAO! No,,,, was looking at a link in a Forum thread and thought I would see whats going on here.


BC

 

[Junkman2008]

Well, wherever you go, you're an asset. Welcome to the forum. Make sure you come see me over at DC too.

 

[abucfan]

Thank God for this forum

I replaced my battery last Sunday and right after my ac would blow cold thru the passenfer vents and hot air thru te drivers vents. I followed this procedure and now I have cold air out of all vents. Thanks for the help every one.

Allow me to post a correction in the fix for recalibrating the HVAC. What the OP posted as the fix is slightly off, although it worked for him. The correct procedure is:

Re-Calibrating Actuators

Use the following steps to perform the calibration update:

1. Turn OFF the ignition.

2. Remove the battery positive voltage circuit fuse of the HVAC Control Module (fuse 27, located in the passenger's side floorboard by the BCM).

3. Wait 60 seconds.

Important
The module memory will not clear if the battery positive voltage circuit fuse is installed in less than 60 seconds.

4. Install the fuse.


There is no need to disconnect the battery whatsoever.

 

[Junkman2008]

I replaced my battery last Sunday and right after my ac would blow cold thru the passenfer vents and hot air thru te drivers vents. I followed this procedure and now I have cold air out of all vents. Thanks for the help every one.

Glad that worked for you. Now that could be all that was needed. However, your year car has the actuators that are known to go out of range. They fixed that issue in the 2001 and higher Vettes. Also, low R-134a can create the same issue that you've experienced and if your refrigerant is low, that means that you have a leak. Here's what you can do to make sure there is nothing else wrong with your system.

You can have a mom and pop shop do a "evacuation and recovery" of your system. The machine that they use SHOULD be able to not only recover and replace the refrigerant in your system, but also tell you EXACTLY how much refrigerant it recovered (the ACR 2000 was the unit that GM recommended to use when your car was manufactured. Something similar will suffice). This system also has the ability to check your system for leaks. Your year car should have exactly 1.625 lb's of R-145a in the system (.0737 kg) No more, no less. If it does not, then you have a leak somewhere and when they fill the system back up, they should insert some green die into the system to help locate that leak (all AC systems are sealed and will never loose refrgerant unless a leak develops).

Make sure that you check your codes. If your system has a issue, you may throw the B0361 and B0441 codes. Those pertain to your actuators, which you just reset. There's another code that will set if your refrigerant is low but I can't remember exactly what that code is right now. One more important piece of advice. When adjusting your temperature, DO NOT spin the temperature knob very fast. This can cause the HVAC head unit to misinterpret the action and cause you to have the same problem you just fix. The head unit cannot always properly interpret that action so turn the knob normally to slow when adjusting the temperature. So many people made this mistake that GM had to put out a TSB about it so that the technicians could pass that information off to the customers.

Stay cool!

 

[abucfan]

I don't believe I have any leaks. I just had the dealer I bought the vette from replace the ac compressor prior to purchasing the car last month. The old compressor was leaking. The ac had been working great since then up until I replaced the battery last Sunday. I thought that was too much of a coincidence not to be something rather simple. That is what lead me to research the fix on this forum. Again, Thanks.

Glad that worked for you. Now that could be all that was needed. However, your year car has the actuators that are known to go out of range. They fixed that issue in the 2001 and higher Vettes. Also, low R-134a can create the same issue that you've experienced and if your refrigerant is low, that means that you have a leak. Here's what you can do to make sure there is nothing else wrong with your system.

You can have a mom and pop shop do a "evacuation and recovery" of your system. The machine that they use SHOULD be able to not only recover and replace the refrigerant in your system, but also tell you EXACTLY how much refrigerant it recovered (the ACR 2000 was the unit that GM recommended to use when your car was manufactured. Something similar will suffice). This system also has the ability to check your system for leaks. Your year car should have exactly 1.625 lb's of R-145a in the system (.0737 kg) No more, no less. If it does not, then you have a leak somewhere and when they fill the system back up, they should insert some green die into the system to help locate that leak (all AC systems are sealed and will never loose refrgerant unless a leak develops).

Make sure that you check your codes. If your system has a issue, you may throw the B0361 and B0441 codes. Those pertain to your actuators, which you just reset. There's another code that will set if your refrigerant is low but I can't remember exactly what that code is right now. One more important piece of advice. When adjusting your temperature, DO NOT spin the temperature knob very fast. This can cause the HVAC head unit to misinterpret the action and cause you to have the same problem you just fix. The head unit cannot always properly interpret that action so turn the knob normally to slow when adjusting the temperature. So many people made this mistake that GM had to put out a TSB about it so that the technicians could pass that information off to the customers.

Stay cool!