wrong vents on airconditioning function

Discussion in 'Body and Interior: Repairs and Modifications' started by grumpyvette, Oct 25, 2010.

  1. grumpyvette

    grumpyvette Administrator Staff Member

    Hey, Grumpy!
    I heard you were an expert and if you couldn't help me help could not be found! So, here's the deal: I have a 95 coupe, love the car, but I live in Arizona and when the A/C blows out the defrost vents instead of the dash vents it doesn't cool the car down much -- even though the air is cold. Would you give me a place to start looking for problem areas?
    I appreciate your help.



    HAVING A SHOP MANUAL FOR YOUR EXACT CAR HELPS.......WORKING ON A CORVETTE WITHOUT A SHOP MANUAL PUTS YOU AT A HUGE DISADVANTAGE
    http://www.helminc.com/helm/Result.asp? ... ted_media=

    start by pulling trouble codes and checking ALL FUSES
    theres some chance its just a stuck vent door in the air control routing in the duct work,as its possible for light trash like Kleenex to get sucked up into the dash, jamming the door or a vacuum line to be unplugged but it could also be a failed electrical component, unfortunately its going to require partial dis-assembly and inspection and testing so pull codes and think logically, look for loose connectors and use a multi meter

    The AC will only start after it senses a certain temperature.

    Press and hold the fan up/down buttons for 5-6 secs.
    It will show -00.
    Press auto-fan once.
    It will show any fault codes.

    00 means everything OK.
    09 for instance means low on freon.

    There are ten fault codes.

    http://chevythunder.com/199295_lt1_trouble_codes.htm

    toptechx6 posted this info
    "if the green LED above the climate control buttons is NOT flashing when the car is running, there are likely no fault codes stored.
    While you could have a more serious problem such the programmer, the first thing I would inspect is the three port vacuum check valve located under the right side fuel rail cover. It is common for the ports to break off as they become brittle due to age and temperature, when that happens the system defaults to defrost mode for safety reasons.
    The valve, (PN 15733271) is available from the dealer for less than $10, a universal version can also be found at many parts stores (one way vacuum check valve)
    In the pictures below the valve is the black and white plastic piece with three hoses attached, yours may look slightly different. The fuel rail cover is removed by pulling straight up, you can then inspect the valve."

    [​IMG]
    [​IMG]
     
    Last edited by a moderator: Feb 1, 2016
  2. lovemyc4

    lovemyc4 New Member

    Grumpy, you are my hero! My mechanic with all his shop books couldn't find the problem, but with your clear instructions this girl did!
    I pulled the cover fuel cover and checked the valve; found it had holes. I picked up one at the local auto parts place, cost $4.08, and put it on.
    Started the car and guess what? Yep, the a/c now comes out the vents. Now no matter which button I push the air comes out the selected location.
    Next I'm driving over to my mechanics.

    :lol:
     
  3. grumpyvette

    grumpyvette Administrator Staff Member

    thanks for getting back and posting your results,
    Im glad I could help here!

    many people fail to and that's a shame because it can be a valuable aid to future readers of the threads on the site, who might have similar issues!
     
  4. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    http://www.helminc.com/helm/Result....dule=&mscsid=BJUVXMALDJKB9GQ0THUFJ5LAKTTP9VS4
    ECM Fault Code List (LT5; VIN J)
    Code Definition13 Left Oxygen Sensor (Open)
    14 Coolant Sensor (High Temp)
    15 Coolant Sensor (Low Temp)
    16 DIS Fault Line Malfunction
    21 TPS (Voltage High)
    22 TPS (Voltage Low)
    23 IAT Sensor (Temp Low)
    24 Vehicle Speed Sensor
    25 IAT Sensor (Temp High)
    31 Cam Sensor Signal Problem
    33 MAP Sensor (Voltage High)
    34 MAP Sensor (Voltage Low)
    36 DIS Fault Line/Missing or Extra EST Signal
    41 Cylinder Select Error
    42 EST System Malfunction
    43 ESC System Malfunction
    44 Left Oxygen Sensor (Lean)
    45 Left Oxygen Sensor (Rich)
    46 PASS-Key Circuit
    51 MEM-CAL Problem
    52 Engine Oil Temp Sensor (Low Temp)
    53 System Voltage Error
    54 Fuel Pump Voltage Low
    55 Fuel Lean Monitor
    56 Vacuum Sensor Voltage Problem
    61 Secondary Port Throttle System Malfunction
    62 Engine Oil Temp Sensor High
    63 Right Oxygen Sensor Circuit (Open)
    64 Right Oxygen Sensor (Lean)
    65 Right Oxygen Sensor (Rich)
    66 Engine Power Switch Voltage (High or Low)

    ECM Fault Code List (L98; VIN 8)
    Code Definition13 Oxygen Sensor (Open)
    14 Coolant Sensor (High Temp)
    15 Coolant Sensor (Low Temp)
    21 TPS (Voltage High)
    22 TPS (Voltage Low)
    23 IAT Sensor (Temp Low)
    24 Vehicle Speed Sensor
    25 IAT Sensor (Temp High)
    32 EGR System Malfunction
    33 MAP Sensor (Voltage High)
    34 MAP Sensor (Voltage Low)
    41 Cylinder Select Error
    42 EST System Malfunction
    43 ESC System Malfunction
    44 Oxygen Sensor (System Lean)
    45 Oxygen Sensor (System Rich)
    46 PASS-Key Circuit
    51 MEM-CAL Problem
    52 Engine Oil Temp Sensor Low
    53 System Voltage Problem
    54 Fuel Pump Voltage Low
    62 Engine Oil Temp Sensor High

    CCM Fault Code List
    Code Definition
    12 On-Board Diagnostics Operational; No Codes
    13 DIC Switches Open or Shorted to B+
    14 DIC Switches Shorted to Ground
    16 Ignition 3 Fuse Circuit Open
    21 Horn Relay Coil Shorted to B+ or CCM Internal Open
    22 Rear Defogger Relay Coil Shorted to B+ or CCM Internal Open
    24 Courtesy Lamp Relay Coil Shorted to B+ or CCM Internal Open
    25 Courtesy Lamp Relay Coil Circuit Open or Shorted to Ground
    26 LCD Blanking Control Circuit Shorted to B+ or CCM Internal Open
    27 LCD Blanking Control Circuit Open or Shorted to Ground
    31 LCD Data Circuit Shorted to B+ or CCM Internal Open
    32 LCD Data Circuit Open or Shorted to Ground
    33 Data Clock Circuit Shorted to B+ or CCM Internal Open
    34 Data Clock Circuit Open or Shorted to Ground
    35 Data Strobe Circuit Shorted to B+ or CCM Internal Open
    36 Data Strobe Circuit Open or Shorted to Ground
    37 M Clock Circuit Shorted to B+ or CCM Internal Open
    38 M Clock Circuit Open or Shorted to Ground
    41 Loss of ECM Serial Data Communication
    51 Pass-Key - Invalid Key Detection
    52 Pass-Key - Key Detection Circuit Shorted
    53 Pass-Key - Key Detection Circuit Open or Shorted to B+
    54 Pass-Key - Fuel Enable Failure
    61 Pass-Key - Key # 1 Programming Resistance Out of Range
    62 Pass-Key - Key # 2 Programming Resistance High
    63 Pass-Key - Key # 2 Programming Resistance Low
    71 LCD Dimming Output Circuit Shorted to B+ or CCM Internal Open
    72 LCD Dimming Output Circuit Open or Shorted to Ground
    73 LED Display Dimming Output Circuit Shorted to B+ or CCM Internal Open
    74 LED Display Dimming Output Circuit Open or Shorted to Ground

    LTPWS Fault Code List Code Definition
    99 Receiver/Control Module Diagnosis
    23 Right Tire Rear Low Tire
    24 Right Tire Rear Sensor Fault
    33 Left Tire Rear Low Tire
    34 Left Tire Rear Sensor Fault
    43 Left Tire Front Low Tire
    44 Left Tire Front Sensor Fault
    53 Right Tire Front Low Tire
    54 Right Tire Front Sensor Fault

    ABS Fault Code List Code Definition
    21 Right Front Wheel Speed Sensor Fault
    22 Right Front Toothed Wheel Frequency Error
    25 Left Front Wheel Speed Sensor Fault
    26 Left Front Toothed Wheel Frequency Error
    31 Right Rear Wheel Speed Sensor Fault
    32 Right Rear Toothed Wheel Frequency Error
    35 Left Rear Wheel Speed Sensor Fault
    36 Left Rear Toothed Wheel Frequency Error
    41 Right Front Solenoid Valve Fault
    45 Left Front Solenoid Valve Fault
    55 Rear Wheels Solenoid Valve Fault
    61 Pump Motor or Motor Relay Fault
    63 Solenoid Valve Relay Fault
    71 Electronic Brake Control Module Fault
    72 Serial Data Line Fault
    75 Lateral Accelerometer Fault (Short ot Open)
    76 Lateral Accelerometer Fault (Signal out of Range)

    SIR (Airbag) Fault Code ListCode Definition
    21 Steering Column Circuit Resistance too High
    22 Steering Column Circuit Resistance too Low
    23 Steering Column Circuit Voltage too High
    23 Steering Column Circuit Voltage too Low
    25 Short to Battery in Steering Column Circuit
    26 Open in Steering Column Circuit
    31 Open 36 VLT to Deployment Loop
    32 Grounded 36 VLT to Deployment Loop
    33 History Code, Diode B Shorted in Wiring Harness to Arming Sensor
    34 Open in Ignition 1 Feed to Deployment Loop
    35 Discriminating Sensor Open
    41 and / or 42 Deployment Loop Energy Reserve Voltage Fault
    51 Accident Detected
    52 EEPROM Accident Data Area Full
    61 Force Low or "INFL REST" Warning Lamp Circuit Failure
    71 Internal DERM Fault

    Automatic Air Conditioning Fault Code List01 + 02 Temperature Door Motor Circuit Fault
    03 (Open) + 04 (Short) Outside (Ambient) Air Temperature Sensor Fault
    05 (Open) + 06 (Short) In-Vehicle Temperature Sensor Circuit Fault
    07 (Open) + 08 (Short) Solar (Sun-Load) Sensor Circuit Fault Open or Shorted
    09 Low Freon Detected
    10 or --- Uart or "E" and "C" Bus Failure
    Diagnostic mode = push and hold the fan "up" arrow and fan "down" arrow at the same time (5 sec.)
    Push "Auto Fan" to show the fault codes
    LED flash at 60 times per minute = Fault codes be stored
    Reset = Remove Negative Battery Cable for 1 Minute

    Code Liste Selective Ride Control FX3:12 Start of code sequence
    13 Left Rear time out
    14 Right Front time out
    21 Left Front time out
    22 Right Rear time out
    23 Loss of vehicle speed signal
    31 Left Front out of position
    32 Right Front out of position
    33 Left Rear out of position
    34 Right Rear out of position
    41 Selective Ride Control Switch short to Voltage
    42 Selective Ride Control Switch open cantacts
    43 Selective Ride Control Switch open circuit


    you will need a shop manual, and it helps to have a multi meter vacuum gauge and trouble code readers
    http://www.digitalcorvettes.com/forums/showthread.php?t=61402
    every mechanic needs an ANALOG multi meter for testing capacitors with a micro farad scale, AND a DIGITAL MULTI METER
    [​IMG]

    http://forum.grumpysperformance.com/viewtopic.php?f=36&t=63&p=3403&hilit=vats#p3403
    [​IMG]
    use of a shop manual and multi meter can be very helpful
    http://www.totalcardiagnostics.com/toad/

    http://www.corvettebuyers.com/c4vettes/codes.htm

    https://www.autoenginuity.com/

    http://www.ebay.com/gds/Automotive-Diagnostic-Software-Buying-Guide-/10000000177404580/g.html

    http://garage.grumpysperformance.co...lay-switch-locations-and-info.728/#post-54562

    http://www.amazon.com/ScanTool-4258...4?s=automotive&ie=UTF8&qid=1445959029&sr=1-24

    http://www.amazon.com/ScanTool-4230...se_s_cp_3?ie=UTF8&refRID=0AY7FJ8EWKRKCRWRMPZ0

    [​IMG]
    infrared thermometers are a very useful tool to track down issues with tuning, or mal functioning sensors , without verified facts your guessing.
    this is the most consistently accurate I.R temp gun I've used for testing[/img]
    [​IMG]
    http://www.testequipmentdepot.com/e...1100200223789&utm_content=All Extech Products
    INFRARED TEMP GUN

    Wide temperature range from -58 to 1832°F (-50 to 1000°C)
    READ TROUBLE CODES
    http://garage.grumpysperformance.com/index.php?threads/c4-c5-corvette-trouble-codes.2697/#post-51440



    per

    bdw18_123

    Here is how to enter the diagnostic mode of the electronic A/C controller. Taken directly from the 1990 FSM:

    "If a system fault is detected, the LED of the operating mode the system is in at the time of fault detection will flash at a rate of 60 times per second. Fault codes will then be stored.

    To enter into the diagnostic mode, the fan 'up' and fan 'down' buttons must be pushed simultaneously for approximately 5 seconds. Upon entry into the diagnostic mode, the LCD will display any fault codes stored by the programmer.

    FAULT CODES DESCRIPTION

    00................................................NO SYSTEM FAULTS
    01............................TEMP. DOOR MOTOR CIRCUIT OPEN
    02..........................TEMP. DOOR MOTOR CIRCUIT SHORT
    03............................................AMBIENT SENSOR OPEN
    04..........................................AMBIENT SENSOR SHORT
    05.....................................IN-CAR TEMP. SENSOR OPEN
    06...................................IN-CAR TEMP. SENSOR SHORT
    07.......................................SOLAR LOAD SENSOR OPEN
    08.....................................SOLAR LOAD SENSOR SHORT
    09.............................................LOW FREON DETECTED
    10........................................................UART FAILURE

    While in the diagnostic mode, it is possible to check several different system parameters (circuits or systems). This is done by pressing the fan 'up' or fan 'down' button. Once the parameter to be checked has been chosen, the fan 'AUTO' button is pressed and a diagnostic value is displayed on the LCD.

    The following is a list of diagnostic parameters:

    PARAMETER DESCRIPTION

    02............................................IN-CAR TEMP. SENSOR
    03..........................OUTSIDE (AMBIENT) TEMP. SENSOR
    04..............................................SOLAR LOAD SENSOR

    For further diagnosis of ECC system codes, refer to the diagnostic charts in this section. To exit diagnostics, change to a different ECC system mode."

    Find out what codes are stored in your A/C controller, and report here what they are and I will send you the troubleshooting page(s) for that code.



    You should purchase an FSM, while they are a bit pricey, they are worth it if you are going to do any work/troubleshooting on your vette.
    [​IMG] [​IMG]
    0 Comments

    For 90-96
    owners these are the codes you can read from your AC control
    panel.
    To access these codes do the folowing procedure.
    1.
    Press both fan(up and down)buttons together and hold them for roughly 5
    seconds. This will display a 00 on the A/C control panel LCD.
    2.
    Use the fan up and down buttons to select the desired code you wish to
    read.
    3. After selecting the code press button inbetween the fan
    controls. This will display the code information on the A/C
    LCD.
    Here are the codes:
    HVAC Diagnostic codes
    0-
    System Faults
    (one of these will be set if your air conditioning
    controls have an LED flashing)
    00=No Faults
    01= Temp Door Motor
    Circuit Fault
    02= Temp Door Motor Circuit Fault
    03 = Ambient
    Sensor Open
    04 = Ambient Sensor Short
    05 = In-Vehicle Temp Sensor
    Open
    06 = In-Vehicle Temp Sensor Short
    07 = Solar Load Sensor
    Open
    08 = Solar Load Sensor Short
    09 = Low Freon Detected
    10 =
    UART Failure
    1- Temp Setting 60F to 90F
    2- In-Car Temp
    Sensor 10 = HOT -130 = 230 = COLD
    3- Outside Temp Sensor 10 = HOT
    -130 = 230 = COLD
    4- Sun Load Sensor Max light Max Dark
    L98 38
    183
    LT5 115 -110 = 210
    5- Ignition System Voltage 0 = 9 Volts
    -155 = 255 = 16 V
    6- Engine Speed (RPM divided by 25)
    7-
    Vehicle Speed
    9- A/C System Mode
    00 = OFF
    01 =
    Re-Circulation
    02 = A/C
    03 = Bi-Level
    04 = Heater
    06 =
    Defrost
    07 = Vent
    10 = Manual Re-Circulation
    10- Blower PWM
    0 = 0 Volts 128 = 14 Volts
    11- Program Number 00 = COLD -155 = 255
    = HOT
    12- Mix Number -155 = 255 = COLD 00 = COLD
    16- Coolant
    Temperature In degrees C
    17- Solar Correction 114 = Max light 128 =
    max dark
    30- Stored Full Hot Value 0 to 50
    31- Temp Door
    Travel Range 100 to 200
    34- Temp Door Position Requested 00=Full
    HOT -153=253=Full COLD
    35- Compressor On Time 0.1 second
    increments
    36- Number Of Times Below Critical Time
    37-
    Software Version Number


    The early ALDL connector has room for 12 pins however only 7 are populated and of those we are only interested in Pin "A" and "B" for this procedure.

    Remove the ALDL cover (in the unlikely event that there still is one in the automobile...they usually were lost early in the automobile's lifetime) and as you view the pins, you will find the top row fully populated whereas not all are populated pin on the bottom row.

    On the top row (as you view the connector from the cockpit), the pin designators are F,E,D,C,B,A.


    First locate your car's alcl
    this component is located just below the instrument panel and
    to the left of the center console. Remove the plastic cover
    the first two slots to your right are the A & B slots for a drawing of
    the alcl module's picture is added below.
    The A slot is the diagnostic slot and the B slot is the ground
    slot. insert the computer key into these slots (with the engine
    off) this is very important...now only put the ignition key
    to on ( not start !!!) the check engine light will display a
    code 12 which is one flash followed by two flashes.
    this code will be flashed three times ..followed by the
    trouble code stored in your car's computer.
    what ever the code is it will be flashed three times.
    have a paper and pencil ready and write down the
    code .

    code 13 =1 flash followed by 3 flashes =>oxygen sensor
    code 14 =1 flash followed by 4 flashes =>coolant sensor
    code 15 =1 flash followed by 5 flashes =>coolant sensor
    code 21 = 2 flashes followed by 1 flash =>throttle position sensor
    code 22 = 2 flashes followed by 2 flashes=> throttle position sensor
    code 23 = 2 flashes followed by 3 flashes=> manifold air temp sensor
    code 24 = 2 flashes followed by 4 flashes=> vehicle speed sensor
    code 25 = 2 flashes followed by 5 flashes=> manifold air temp sensor
    code 32 =>egr system
    code 33 =>map sensor
    code 34 =>maf sensor
    code 35 => idle air control
    code 41 => cylinder select error
    code 42 => electronic spark control
    code 43 => electronic spark control
    code 44 => lean exhaust
    code 45 => rich exhaust
    code 51 => PROM
    code 52 => fuel calpak
    code 53 => system over voltage
    code 54 => fuel pump circuit
    code 55 => ecm
    code 62 => oil temp
    please remember that if you have the computer key installed
    in the alcl and you start the engine ( you will ruin the engine's computer
    )
    only put the ignition to on (not to start)
    If you should get a check engine soon display.. you can use
    the above procedure and codes to buy the right part
    or at the very least to keep from getting taken for a ride
    and be made to pay hight prices for some inexpensive
    module that you could have installed yourself.
    You never ask a barber if you need a haircut ..
    so you have to be on guard they will see you comming
    a mile away.
    If your engine displays a trouble code ... your engine will
    go into limp mode ..it will still run but very poorly.
    you might be able to reset the computer if it will not start
    ( just to get home ) by disconnecting both battery cables
    and re-installing them ...this is not recommended ..but if
    you are stranded it might help unitl you get your car home
    or to a repair shop..good luck
    http://www.tonkabaygroup.com/vette/c4codes.html
    [​IMG]
    http://www.c4vettes.com/ecm.htm
    [​IMG] [​IMG]
    http://chevythunder.com/199091_corvette_1227727_ecm.htm
    [​IMG]
    [​IMG]
     
    Last edited: Aug 29, 2017
  5. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

     

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