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Blower Motor Problem

Discussion in 'Chevy Trucks' started by Caleb55, Dec 6, 2006.

  1. Caleb55

    Caleb55 Member
    Messages: 44

    I've got a '95 2500 that had the blower motor going out. Would squeel worse than a fat hog on all speeds. Then it would only work on high. Changed it out yesterday and the new one works fine, but it will only work in high as well. All the other speeds I've got nothin. :realmad: Would really like to get this figured out soon. Truck does have AC if that changes anything.
  2. Ding

    Ding Member
    Messages: 62

    The power feed for all speeds other than high come from a different source and go though one or both of the resistors above the blower. There is a simple diagnostic test that can be performed in the Helm (Official GM) service manual (in Volume 1 of the 4 volume set).

    If you do not have access to one of these maybe I can post the procedure for you or scan the page and email it to you.

    Check the fuse inside the cab (by the door pillar) first.
  3. Caleb55

    Caleb55 Member
    Messages: 44

    Fuse looked good when I checked it. If you could, send me that info. Thanks!
  4. yzf1000_rider

    yzf1000_rider Senior Member
    Messages: 147

    Under The Hood There Is A Red Wire Close To The Firewall On The Passengers Side It Goes To A Plug That Has About 4 Wires In It Green Brown And I Think Yellow But Check The Connection At That Plug. Hope It Helps
  5. Ding

    Ding Member
    Messages: 62

    It is likely one of the following items . . .
    1. The blower resistor assembly is disconnected.
    2. Other wires are disconnected or loose in that area, try the wiggle test.
    3. The blower motor relay is disconnected or failed. Pull the relay (in plenum near blower motor) and check cavity B2 in the socket for power (to ground) with ignition ON, and heater on and in the LO speed. If power exists then the relay may be bad. No power then continue to next step.
    4. With relay still out, ignition ON and heater in LO, pull the blower resistor connector (above the relay on top of plenum) and test between cavity B in the connector socket and cavity B2 in the relay socket for power. If test lamp lights (and did not in previous step) the blower resistor is bad. If lamp does not light continue with next step.
    5. With ignition ON and heater in LO, check between cavity B in blower resistor connector socket and ground. If test lamp lights then the DK BLU wire between the resistor and the realy has a break in it.

    Basically power gets to the blower motor from the blower motor relay for all speeds. The blower motor relay switches between full power input from the fuse under the hood (HI), to power feed from the blower motor resistor (the thing that actually controls how much power), depending upon the fan switch setting (LO, MED1, MED2). The blower resistor gets power from the fuse in the cab by the door pillar.

    Good luck, if you get stuck post your progress.
    Last edited: Dec 9, 2006
  6. aus316

    aus316 Member
    Messages: 51

    GM tech here u need a blower motor resistor :gunsfiring: :gunsfiring: good luck may the snow be with u:gunsfiring: :gunsfiring:
  7. Ding

    Ding Member
    Messages: 62

    The tests I posted above will prove what is wrong rather than simply replacing the most likely. When it is my nickle, I like to only replace parts that I have proven are faulty instead of running up the bill with "shotgun diagnostics".

    As yzf1000_rider says though, it is most likely the resistor if all the wires are connected correctly.