Hi I've searched the forum under climate control and heater and haven't found my problem. Hopefully someone can help... I have a 98 and while adjusting the driver's climate control, it got stuck at 79-82 degrees, no matter how you turn it. Any quick fixes or is this a tear apart kind of thing for a skilled mechanic? Thanks for any help. And I'm a non-mechanic girl so please don't get too technical :]

 

Have you pulled your codes yet? After doing that first, you might try pulling fuse 27, waiting a bit then put it back in.

 

I had the same problem on my 98. You will have to replace it. I checked with a couple people that repair them and they said it wasn't repairable. I got a new one on ebay for $200.00. It was over $400.00 at the dealer.

 

Before you get too involved in replacing the unit, pull the DTC and see if any HVAC DTCs are set. If they are clear the DTCs and see if that makes a difference.

If you not famulair with reading your own DTCs using the DIC,,,heres the entire procedure and some instructions:

READING YOUR Engine Diagnostic Codes



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 ect)
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 C code indicates a malfunction is present and active 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 English/Metric (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 and hold the RESET button 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. You can GOOGLE the DTC and also find information on it.




Here is very good site that explains the DTCs:


http://www.corvette-web-central.com/C5DTCcode.html


http://www.obd-codes.com/trouble_cod...d-ii-codes.php



Make sure to include the H or C suffix!!



Like dgrant3830 stated, try pulling the fuse and then reinstalling it. When I get home I will see if there are any other fuses to check/pull por power to that module.

It could very well be a defective HVAC controller but, I like to do some digging first to keep you from spending money that you dont need to.

BC

 

I have the same trouble with mine, the drivers temp will not adjust when you turn it - it'll just fluctuate between 69* & 70* - and I have even noticed that the "OFF" button will stop working, it will not allow it to be turned off unless I shut the Vette off when I stop somewhere!

I checked into it and decided to pick-up another Head Unit from a wrecked '02 ($100.00 from a local forim member) and I have it ready to install - when I pull the old unit out I will pull it apart and see what is up with that area on the Head Unit and report back any findings

I had no codes at all for the unit and everything else is good, so I keep all informed

Thanks,Matt

 

Matt & Siaran

DELPHI's soldering quality is very sub-par. In fact, Ive see junior high school votech students solder better than what you will find in that controller.

What I would do is pull the unit apart and look for cold solder joint and or loose resistors (little square brown objects on the board) and if you find any, just touch up the poor solder joint. I felt good about my HVAC Controller until just the other day. I have the dreaded dark display. Same issue. POOR SOLDER JOINTS!

I'm going to take mine apart and re-solder the resistors.

If you cant solder, take the unit to a TV Repair shop and have them look at it. Ask them how much it cost to examine it and touch up any poor solder joints before you just tell them to do it???? If its any more than $25-$30,,$50 at the most,, you may want to pass.

Heres the fuses for that unit:

Instrument Panel Fuse Box (passengers foot well =
HVACCON Mini Fuse# 27

 

Will do Bill

I was gonna look for it everywhere and picture document my findings - even if it gets sacraficed

I got the newer one in hand (30,000 miles on it) and will slap it in and work on the '98 (perhaps at work and see what is up in there) I did the dark dimm light fix 15,000 miles ago and it still looks great but the dang temp dial is taking the dump now

I have had this one aprt before as well as others to fix their dark dimm led display so now I am looking forward to the rest of this beast

PS- Bill, the ABS Module connection NO/COMMUNICATION problem is fixed, thanks for all the help
Thanks,Matt

 

Thank you everyone for your advice. As I said, I'm no mechanic, and I've never tried playing with the codes, but once again, I've been given lots of good advice that gives me a place to start and will help keep me from getting ripped off. It's very much appreciated!!

 

Reading this makes me glad I have the manual HVAC control head. Good luck with your fix.