Air vent issue

Discussion in 'OEM and Custom Interiors' started by 98chevy2500SS, May 3, 2021.

  1. 98chevy2500SS

    98chevy2500SS Specializes in Accessories 101

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    This is weird... For some reason, when I'm using A/C, the vents will randomly shut off. Sometimes it takes 20-30 minutes, sometimes 10 minutes, etc. The blower motor is still running and A/C compressor is on, but for some reason air won't come out of the vents after a while of driving. When I have the A/C OFF, with just outside air coming in, the vents work perfectly. I have lubed up the actuator, and made sure it is still working. Anybody have a clue as to what's happening with this? To get the vents to start blowing again, I have to flip around with the switch and then it will start blowing again. I should mention it does NOT default to defrost when this happens. I am at a loss of what could be the issue. Hopefully that all made sense..

    Edit: truck is a 1997 Chevy K1500.
     
    Last edited: May 3, 2021
  2. SUBURBAN5

    SUBURBAN5 I'm Awesome

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    Sounds like an actuator? Is your control module original?
     
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  3. 98chevy2500SS

    98chevy2500SS Specializes in Accessories 101

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    Actuator works. Control module however, is not original.
     
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  4. SUBURBAN5

    SUBURBAN5 I'm Awesome

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    Whenever my vents were acting wierd it ended up being a wiring issue behind the module. Heated up so bad the harness was melting
     
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  5. AK49BWL

    AK49BWL GMT400 Forever!

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    Yeah, kinda sounds like wiring or the control module, not the actuators. The modules are known to use inadequate transistors for load switching, and you probably have one about to fail.
     
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  6. 98chevy2500SS

    98chevy2500SS Specializes in Accessories 101

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    Thanks guys. I had a brand new spare control module laying around in the garage, so I threw that in this afternoon. Hopefully that fixes it. If not, I'll probably have to diagnose further or just deal with it.
     
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  7. mr_josh

    mr_josh Newbie

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    Evaporator core freezing up, maybe?
     
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  8. SUBURBAN5

    SUBURBAN5 I'm Awesome

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    When you take out the control module look at the wiring harness for melted wires. These are notorious for this issue
     
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  9. 98chevy2500SS

    98chevy2500SS Specializes in Accessories 101

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    Not sure on that, when I switched to the floor vent for around 10 seconds, then flipped back to the front forward vents, it starts to work again so I don't think it would be that.

    Thankfully no melted wires. :waytogo:
     
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