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F*%^ing Heater

Discussion in 'The Garage' started by Swanson52, Oct 23, 2002.

  1. Swanson52

    Swanson52 1/2 ton status

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    Ok, my heater does not blow air, and I can't seem to find the problem. /forums/images/graemlins/angryfire.gif Here is what I have checked/replaced; fan switch, fuse, blower motor, and the fan relay. I have power going TO the relay, but not to the blower motor. I would rather NOT run 12v switched to the fan. What have I overlooked?
     
  2. HarryH3

    HarryH3 1 ton status Author

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    Hmm, it should get voltage through one part of the relay or another, depending on the fan setting. On the first 3 settings the power goes through one contact in the relay and then to the resistor pack. Each setting selects a different resistor to route through, wihch determines how much voltage actually reaches the blower. When you flip the switch to high, the relay turns on and sends full voltage to the blower motor, bypassing the resistor pack completely. With 2 different circuits at work you should get the fan running on at least some setting.

    When are you seeing the 12 volts at the relay? If it's only on the high setting, perhaps what you're seeing is the 12 volts that energizes the relay, rather than the 12 volts that would go to the blower motor.

    Oh yeah, all this assumes that your truck has a/c also. I've never had one without it, so I don't know if GM used a different setup on the heater-only trucks. /forums/images/graemlins/frown.gif
     
  3. Swanson52

    Swanson52 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    When are you seeing the 12 volts at the relay?

    [/ QUOTE ]

    Sorry, I have power at the relay, but I used a test light rather than a voltmeter. There is always power there (due to the reasons you stated), but fan no worky. Could I have gotten 4 bad relays in a row (3 used and 1 new)??
     

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