Blower doesn't blow very well

Discussion in 'GM 6.5 Diesel Engines' started by Extremesounds13, Dec 8, 2010.

  1. Extremesounds13

    Extremesounds13 New Member

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    I did some searching and found no answer so here goes. My blower for the heater doesn't seem to blow very hard even on high. I put a new blower in last winter from checker auto parts cause my other one squealed and I seem to remember it working good when I put the new one in. I did notice this summer when I ran the A/C that it didn't blow overly hard but now that its real cold out I know its not blowing hard enough. When its on high and on the defrosters it blows ok but not real hard but when you switch to the dash vents it barely blows out of the four vents. Do you think I have another bad blower motor or could it be a wiring or maybe a ground issue? Is there a way to know how hard it should blow? Is there a more powerful blower motor I could swap in?
     
  2. ak diesel driver

    ak diesel driver Active Member

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    it's most likely a gound/connection problem or a door problem
     
  3. WarWagon

    WarWagon Well it hits on 7 of 8...

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    Check the voltage at the blower motor on high.
    Look around and above the blower motor area for a connector with two heavy wires in it.

    You know the melted one?

    1995's are famous for this connector meltdown and my 1993 doesn't look so good.

    Replace the connector and add a extra ground from the blower motor.

    Also you can have a dirt plugged evaporator. Remove the blower motor and vacuum out the evaporator coils. Then use a garden hose and towel to spray it clean with scrubbing bubbles.

    Also check the rec door operation.
     
  4. schiker

    schiker Active Member

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    Can you distinguish lo, medium1, medium2, and Hi speeds? Connector or speed resistors maybe. You could measure voltage at motor and see if it is changing. Does it blow hard on floor? Actuate the mode and see if the rods move smooth look at left side transmission tunnel under dash on the black ac duct box. Do you feel any "leakage" from other vents when on dash mode? Hook up fused jumper directly to the blower motor and see if it blows harder. I made a long lead from a lamp cord with alligator clips for things like this.

    Ground for the blower motor is wired back through the wiring harness and ties to the passenger rear block ground AFAIK.
     
  5. Turbine Doc

    Turbine Doc Just Another Diesel Guy

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  6. Turbine Doc

    Turbine Doc Just Another Diesel Guy

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  7. bison

    bison Active Member

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    Usually the high speed setting is the only one still working after one and two fail.

    I would look for non working flap door or a plugged AC core blocking air flow(i had the latter happen on my 89)
     
  8. Crankme69

    Crankme69 New Member

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    On my 95's many times I need to shut off the blower FIRST then change the selector from heat to defrost, then turn the blower back on & it will move the door to the new position to correctly direct the air flow to the new desired selection.
     
  9. Extremesounds13

    Extremesounds13 New Member

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    So I checked today for that plug but I don't have any plug in the wire. I have a black ground wire to the blower for ground and then the power wire is a purple wire that runs directly up behind the glove box and goes into that pack of relays on the heater core inside the truck.
     
  10. dkanderson

    dkanderson New Member

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    mines the same way but somtimes it goes low to high i havent really had time to mess with it
     
  11. Turbine Doc

    Turbine Doc Just Another Diesel Guy

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    Did you remove the the glove box door all way out IIRC purple wire is for the PCM communications bus
     
  12. racer55

    racer55 New Member

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    On a 90's gasser 1/2 ton I used to own the door motor control rod would veroften get blown/shaken off of the door rod,there are several door servos on these trucks to direct airflow.When the door gets caught 1/2 way the flow volume is greatly reduced.
    The one I had trouble with is on the drivers side near the steering column level and was not too hard to see hanging in the breeze.
    The soloution in my case was to dab some rtv silicone on the door rod and poush the lever back on,the added grip of the silicone held it there for over 10 years.
     
  13. racedaymechanic

    racedaymechanic Supporting Vendor

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    On mine I lost High just about no air flow on high, I put a new AC Delco Blower motor Resistor on and that was it, 20 bucks at Advance, Kinda a pain to get at its on top of the heater/ac box behind the glovebox, but it is what failed on mine
     
  14. great white

    great white Active Member

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    Can you hear it changing speeds and switching from each position? Including High?

    If so, follow warwagon's advice on cleaning out the evap core.

    My blower was working fine but wouldn't blow much harder than a popcorn fart on the dash vents.

    Turns out the evaporator core was covered with a blanket of dog hair from the PO's chocolate lab.
     

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