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AC wiring

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 85K5inGeorgia, Jul 1, 2002.

  1. 85K5inGeorgia

    85K5inGeorgia Registered Member

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    Okay, it is hot here in Georiga. I thought that I could go through this summer without looking at my AC system but my wife won't ride in my K5 without the AC. Here is my question, I do not have any power at the compressor. I have checked the plug with a test light and I am not getting anything. I have traced the wire back to the plug at the blower motor and still no power. Any ideas on what could cause this? I have also tried to find a service manual that I could buy that would show this. No luck on this either. Does anyone have a shop manual for a 85 that could scan the wiring diagram and email it to me? Any help would be greatly appreciated!
     
  2. 95 Silverado

    95 Silverado 1/2 ton status

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    I'm pretty sure the power for the clutch starts at the fan switch, it won't kick in unless the fan is running, and goes to the pressure switch on the accumulator (silver cylinder by evaporator box) and then goes to clutch coil, second terminal on coil goes to ground, sometimes through a high pressure switch on the back of the compressor. I'll check and see if I can find a diagram for you.
     
  3. 85K5inGeorgia

    85K5inGeorgia Registered Member

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    Once I kicked the AC on, I checked the plug at the accumulator. No power. Does the power go from the dash to the plug at the accumulator? If I trace it back to the plug at the accumulator, where does it go from there? Also, there are 2 wires that lead from the compressor, one I am tracing and the other stops near the carb with a plug end. I don't see anywhere to plug it into. Any ideas on where that is supposed to go?
     
  4. BlazerGuy

    BlazerGuy 3/4 ton status

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    Just take the top off!! /forums/images/icons/wink.gif /forums/images/icons/laugh.gif
     
  5. 85K5inGeorgia

    85K5inGeorgia Registered Member

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    Oh, trust me, I do that every chance I get. Hell, it is too hot now to even ride with the top off during the day.
     
  6. 95 Silverado

    95 Silverado 1/2 ton status

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    Sorry, I don't have a diagram to show you, the power should start at the heater/AC switch and then go out under the hood. that second connector by the carburetor was probably for the high idle solenoid, it raised the idle speed when the AC was on.
     
  7. 85K5inGeorgia

    85K5inGeorgia Registered Member

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    Thanks for the help! Does anyone know where I can get a Helms Shop Manual for my 85?
     
  8. porkchop

    porkchop Registered Member

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    The first things first. you will need to jump out the low pressure switch to make sure your compressure is working you do this by un pluging the switch and just jump a wire across use a 10 gauge wire to do this this will make it think it's at full pressure. If that doesn't work then you have a bad compressure.
    Hope this helps you a bit.
     
  9. Sandman

    Sandman 3/4 ton status Author

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    I had the same problem and it was because the system pressure was to low also. So do what porkchop said and bypass the switch.
     
  10. 85K5inGeorgia

    85K5inGeorgia Registered Member

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    Where is the low pressure switch? Is that by the accumulator?
     
  11. porkchop

    porkchop Registered Member

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    It will be located just pass the The A/C heater case where the blower motor is on the passanger side of the truck under the hood you will see a double plug wire that plugs into the A/C LINE that the plug to pull of now just jump the wire start the truck and put on the ac now the compressor should go on.
     
  12. 85K5inGeorgia

    85K5inGeorgia Registered Member

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    Okay, I am going to do that. My next question is, what happens if the compressor kicks in? Or, if the compressor still has no response?
     
  13. Sandman

    Sandman 3/4 ton status Author

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    If the compressor kicks in after jumping the switch, go get your system charged up. If it does not you can try jumping a wire directly from your battery to the post on the compressor and see if that kicks it on. If it does then it is a wiring problem. If it does not, Your compressor might be bad.
     
  14. 85K5inGeorgia

    85K5inGeorgia Registered Member

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    Thanks for the reply. I am going to try that this weekend and find out what happens. Stay Tuned!!
     

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