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Blower stopped working

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by djm, Feb 24, 2002.

  1. djm

    djm Registered Member

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    Aside from the fuse frying, where should I start first? Does the blower unit rely on other parts to work? Where are they located? It doesn't work at any speed. Any ideas? Thanks, Dan<P ID="edit"><FONT class="small">Edited by djm on 02/24/02 09:45 AM.</FONT></P>
     
  2. 87GMC

    87GMC 1/2 ton status

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    There is a relay mounted under the hood. It's usually mounted on the side of the heater box near the heater hoses.
     
  3. chevyfumes

    chevyfumes Court jester

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    Watch for the muzzleflash!
    If you end up going to the junk yard for a new one make sure you get one thats heavyduty.(since you have AC)They're easy to replace and cheap about ten bucks...

    <font color=blue> I'd rather have a bottle in front of me, than a frontal lobotomy!
     
  4. behemoth

    behemoth 1/2 ton status

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    Mine's doing (or not doing) the same thing - except it'll work when it wants to. There is no set pattern to when it'll decide to work or not. Could the switch on the dash be a factor? I've ruled out any type of fuse problem.

    behemoth K5
    "Better to remain silent and be thought a fool -
    than to open your mouth and remove all doubt"
     
  5. Stomp

    Stomp 1/2 ton status

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    Try hooking your bloower motor up directly to the battery. If it works fine with direct power, its a good possibility that its the speed selector in the dash

    <a target="_blank" href=http://www.geocities.com/custar/index.html>My truck</a>
     
  6. behemoth

    behemoth 1/2 ton status

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    ... I guess I could pull the relay off and do a continuity check on it. That way I could rule out the relay or determine if that's the problem. Thanks for the info (and ideas).

    behemoth K5
    "Better to remain silent and be thought a fool -
    than to open your mouth and remove all doubt"
     
  7. chevyfumes

    chevyfumes Court jester

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    Watch for the muzzleflash!
    If it is the motor you could try one last thing and that is to drill a small hole a little above the nipple on the outside housing and drip some oil in there...MMMM oily nipples[​IMG]

    <font color=blue> I'd rather have a bottle in front of me, than a frontal lobotomy!
     
  8. mike reeh

    mike reeh 1/2 ton status

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    the most common part to go out is the blower motor resistor... on my '77, its mounted to the AC box, two screws and it pulls out.. has a bunch of springs on it that create resistance for the different speeds.. check that first... usually if all the spring connections are good, then its fine... next is the relay but the relay only comes into play on MAX/HI.. otherwise all the voltage for the blower actually runs thru the wiring harness and thru the switch in the cab.... if you pull the cover on the relay, you can manually "engage" the relay and see what happens to help you narrow it down... next Id say is the switch, but i rarely see those go out (although mine did once. go figure) .. dealer stocked that item and it was cheap..

    all this is assuming the blower motor itself is good.

    One thing thats even more common than all those things, is the wiring harness around the blower motor &amp; components burning up.. usually due to bad ground.. make sure your ground is good, right around where the wiring harness hooks up to the relay, there will be a black wire coming out and it should goto the firewall above the blower motor..both the blower motor and the relay ground at the same spot (in '77 and probably most years) .... that was the source of most of my problems..

    in some years there was an in-line fuse AND/OR fuseable link in the wiring harness.. it was in the big red wire that runs along the top of the firewall, between the relay and the 12 volt junction block on the drivers side.. you know, that black thing with two threaded posts.. yeah.. well check those things out, Ive went thru about every problem with my AC system over the years.. if you have a '77 or close to it, let me know I'll scan in the diagnosis flow chart and/or wiring diagram from the factory manuals.. good luck - keep us posted

    mike
     
  9. djm

    djm Registered Member

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    I really should've read the archive before posting. I found a list of things to check and sure enough it was a simple loose ground wire on the motor. Thanks.
     
  10. chevyfumes

    chevyfumes Court jester

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    Watch for the muzzleflash!
    Now you know every other possible ailment and cure for the GM blower motor...[​IMG]

    <font color=blue> I'd rather have a bottle in front of me, than a frontal lobotomy!
     
  11. behemoth

    behemoth 1/2 ton status

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    FYI - Just to let you all know that a brand new Heater Blower Relay costs $12.91 from the Chevy dealer and it's a genuine AC Delco part. It took all of 45 muinutes to take it off, go get a new one and put it back on. Thought you'd like to know.

    BTW - Thanks to all who provided info on this and to DJM for starting the thread.

    behemoth K5
    "Better to remain silent and be thought a fool -
    than to open your mouth and remove all doubt"
     

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