tbevins

My A/C was blowing hot out of the driver/center and cold out of the passenger two vents, I installed a new driver side vent door actuator and now sometimes it works correctly and sometimes it does the exact opposite..hot on pass..cold on driver side..

Also it seems to me that it also never blows at max velocity, before I installed the vent actuator this was an issue as well, like it blows 75% not 100% it does not blow any harder on auto than if I max out the increase button..

Any help is much appreciated.

Bill Curlee

Pull up the DTCs and see if you have any HVAC DTCs set.. If so, CLEAR THEM and see if the the isue goes away. After you clear them, see if they come back. Report findings

Do you have 100 % control on there the AIR comes out of the vents (i.e. defrost, center venrs, lower vent) and does the air come out of multiple locations at the same time??

The HVAC Blower fan dumps its air into the plenum where the evepator sets. IF,,, there is dirt, paper, leaves, dust etc etc... in front of that evaporator, it will not allow full air flow. Also, if the plenum is full of condensate water, it will flow less air.. Is the evaporator condensate properly draining when you run the AC????? Should see water dripping under the car near the passengers tire area.

When you increase or decrease FAN SPEEDS, does each change if speed increase or decrease the actual fan speed
What AC Systen do you have? Dual Zone or Manual???

READING YOUR C5 Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

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 the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and 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 module. ( 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 types 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. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

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.

NOTE and a WARNING. You can read the DTCs while the engine is running. I pull mine up all the time while driving.
WARNING. Don’t become distracted while reading DTCs while your driving and cause an accident!!!!! Use common sense and drive safe.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

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

Make sure to include the H or C suffix when you post your DTCs!!

NOTE!!! Start the car and let it idle. Then take it for a drive and cause the problem to occur. When you return home pull the codes BEFORE you shut off the engine.


Do NOT discount the codes with the H following them. They can provide an audit trail for issues going on with the car. They ARE important in diagnosing problems.

Post ALL the codes that you pull with the engine running..........

Some codes go away WITHOUT setting an H code when you shut the engine off. I suspect you will have several codes that will show C or HC that do NOT show when the engine is turned off.

tbevins

I just replaced the battery, and topped off the 134 erased all the codes again it had codes for bad ground to right actuator door and same actuator out of range. Keep in mind that last week I had codes for the drivers side actuator and none for the right, so i replaced the drivers side actuator, it was fukdup...but there were no pass side codes then, now there are right side codes all of a sudden and the problem has reversed from cold right / hot left to cold left / hot right.
after clearing codes,new battery,topped 134 it ran around the block cold on both sides but only blowing 75% out of vents...15 min running cold both sides checked and got the codes for the right side actuator ground and out of range, but its cold both sides till i deleted the codes and the thing proceeded to start blowing hot out of the right . I'm going to burn the thing to the ground....

new info
temp **** works turns hot to cold but when turned to cold the vent blowing hot stays hot.
when increasing fan speed w up/dun arrow button display shows increase/decrease however many times will not increase fan speed sometimes it does some times it does not.
While pushing buttons one time randomly I believe the fan blew harder than it ever had, possibly 100%. As soon as I turned **** down it went down but back up to only 75% , never could get it back to that high speed again.
Cleared codes right door out of range comes right back on consistently within seconds along INTERMITTENTLY with right short to gnd appearing sometimes.
It does blow cold on both sides intermittently at 75% blowing speed, especially if i don't clear codes. I don't want to climb in and replace a right side actuator if there is a malfunction in the hvac head unit itself and the actuator is just a tease, it never ever had a code for the right actuator prior to replacing the left actuator.

Also, dual cc, it changes to defrost, but auto button while hot outside used to increase to max cold speed and temp, now pressing auto minimizes fan speed .. water drips off by pass side tire, all normal, fan speeds go up and down w button, BUT NOT ALL THE WAY UP ONLY TO APROX. 75%....

That's about everything I can describe and I am leaning towards a fubar head unit...?