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  1. #1
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    Corvette(s)
    1981 two tone silver over blue

    Default heater and a/c fan

    Good morning i just bought my first ever corvette, a 1981 two tone silver over blue car with 63000 miles car is all original but the heater a/c fan dont work can someone help me, which fuse in the fuse box runs this also noticed in the fuse box where the 35 amp cb goes there is a regular 30 amp fuse also the top left 7.5 amp fuse when tested was not hot changed fuse and still no power to the test points on top of fuse i can do some mech work just not real good on electric problems thanks guys for any help

  2. #2
    Member TimAT's Avatar
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    1969 LS-7 BB

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    The fan does not run in any switch position? The heater blower is a good place to "cut your teeth" on electrical problems- it's a simple circuit. You need a 12v testlight. 2 wires going to the fan motor- a large purple one and a black one. Black is the ground, and usually attached to a tab on one of the mount bolts. Key on, check for power at the purple wire- if the switch is in a low position the light will be a little dim. if the light comes on, then check the ground to the motor. IF there's no power at all, there is a resistor in the top of the heater box.

    And the wiring diagram:

    http://www.nrjvette.com/johdotukset/...tte%201981.pdf
    If anyone has extra horsepower not doing anything, I can always use more.

  3. #3
    Member 6880 Mike's Avatar
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    1968 convertible; 1980 L-82

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    Do you have an owner's manual for your 81? The owner's manual has a diagram of the fuse block and a list of the correct fuses.

    Is your 81 from St. Louis or Bowling Green?


  4. #4
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    1981 two tone silver over blue

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    Quote Originally Posted by 6880 Mike View Post
    Do you have an owner's manual for your 81? The owner's manual has a diagram of the fuse block and a list of the correct fuses.

    Is your 81 from St. Louis or Bowling Green?

    just got the car and it didnt have a book but i have got a diagram off of this forum and it shows a 35 amp like square circuit breaker above the turn signal flasher and mine just has a regular 30 amp fuse in it the car is a two tone from Bowling green

  5. #5
    Member TimAT's Avatar
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    1969 LS-7 BB

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    All the breakers I've seen are normally in high load circuits- like the power windows. Not saying that the breaker in your car is the one for the windows, just that normally GM used them in that circuit.

    If you don't have them yet, the GM service manual and AIM will be an asset you should explore, along with the correct owners manual.
    If anyone has extra horsepower not doing anything, I can always use more.

  6. #6
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    1981 two tone silver over blue

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    Quote Originally Posted by TimAT View Post
    All the breakers I've seen are normally in high load circuits- like the power windows. Not saying that the breaker in your car is the one for the windows, just that normally GM used them in that circuit.

    If you don't have them yet, the GM service manual and AIM will be an asset you should explore, along with the correct owners manual.
    just looking at the diagram of my fuse box and then my car there is a 30 amp cb in the top middle of my diagram and in my car there is a silver breaker looking thing in that slot and on the same diagram there is another 35 amp cb just above the turn signal flasher but my car has a 30 amp regular fuse in that spot does that make any differece

  7. #7
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    1981 two tone silver over blue

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    Quote Originally Posted by TimAT View Post
    The fan does not run in any switch position? The heater blower is a good place to "cut your teeth" on electrical problems- it's a simple circuit. You need a 12v testlight. 2 wires going to the fan motor- a large purple one and a black one. Black is the ground, and usually attached to a tab on one of the mount bolts. Key on, check for power at the purple wire- if the switch is in a low position the light will be a little dim. if the light comes on, then check the ground to the motor. IF there's no power at all, there is a resistor in the top of the heater box.

    And the wiring diagram:

    http://www.nrjvette.com/johdotukset/...vette 1981.pdf
    i checked the fuse its hot only power i have on resistor or relay is the red wire that goes to the engine does the power go to switch on inside of car before it goes to relay or resistor thanks a ton for the help so far just getting some what upset i cant figure this out

  8. #8
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    Corvette(s)
    '81 Black

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    With the key in the "on" position you should have 12v on the orange wire I think.
    But if you have enough knowledge about electrics you can remove the relais and crosswire the red and purple wire, this way direct 12v are running to the blowermotor. I think that if you crosswire the red and orange wires with the relais still in place the relais should work normally, if I'm incorrect you could also smoke your relais

    Greetings Peter

  9. #9
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    1981 two tone silver over blue

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    Quote Originally Posted by Peer81 View Post
    With the key in the "on" position you should have 12v on the orange wire I think.
    But if you have enough knowledge about electrics you can remove the relais and crosswire the red and purple wire, this way direct 12v are running to the blowermotor. I think that if you crosswire the red and orange wires with the relais still in place the relais should work normally, if I'm incorrect you could also smoke your relais

    Greetings Peter
    Good morning my friends after days of checking this and that i fixed my blower motor problem by running a hot wire from the ignition side of fuse panel to the brown wire on top of the resistor which is on top of heater box now the fan works on all speeds once again thanks for all the tips and diagrams

  10. #10
    Member TimAT's Avatar
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    After I read your fix, I went back and looked at the wiring diagram again. I'll bet the bulkhead connector for the HVAC has burned pin 50.
    If anyone has extra horsepower not doing anything, I can always use more.

  11. #11
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    1981 two tone silver over blue

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    Quote Originally Posted by TimAT View Post
    After I read your fix, I went back and looked at the wiring diagram again. I'll bet the bulkhead connector for the HVAC has burned pin 50.
    Once again thanks to all the people and all the help my next thing to tackle is my cruise control not working and i need to repair the antenna mask cable so it will go up and down the previous owner said motor worked but cable broke so he unpluged it also trying to find what the name of the hose that comes out of the front center of air breather thats about 1 inch in dia that goes fwd and makes a 90 degee turn into what looks like some type of smog system need to order one mine is broke and gone except the 90 degree part is still on the car the original part number from gm was 14031168

  12. #12
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    '81 Black

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    For the antenna there are several topics on that subject so do a search.
    The plastic front piece is a smog part but I don't think you can order it as a aftermarket part. Maybe try your local salvage yard. Please also try to put some ... or ,,, in your replies. It's not very easy to read everything in one line

    Greetings Peter

  13. #13
    Moderator bill81vette's Avatar
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    Corvette(s)
    1981 dark blue metallic

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    as for the smog part for the front of your air cleaner,good luck finding one,
    I've been looking for several of them for a few years,
    and they are not out there any more...
    as for your antenna,check the corvette vendors, I bought several last year...
    Bill and Gail...save the wave
    NCRS member 42415
    1981 St.Louis car #2735
    all matching numbers

    born Sept 18,1980
    Cruisefest 2008
    Cruisefestous 2009
    Cruisefest 2010
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    Cruisefest2012



    Without Trucks......
    You would be Hungry,Homeless and Naked!!!!!!



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