Outdoor AC unit works, indoor blower won't turn on

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Old 05-08-18, 07:03 PM
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Outdoor AC unit works, indoor blower won't turn on

My AC is having problems. When I turn it on, the outside unit kicks on but the blower on the inside unit does not. The outside unit quickly freezes because the inside unit doesn't turn.

Here's the problem - the blower works just fine when I turn on the heat. However, if I try to switch the fan from auto to on, the blower turns off...

Any suggestions? I am very confused...
 
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Old 05-08-18, 07:30 PM
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Welcome to the forums.

Is this a gas furnace with split A/C ?
Heatpump ?

If it's a gas furnace were going to need it's model number. It's inside on the side wall near the burner.

Most units have multiwinding/multispeed motors. It's possible that the FAN ON/cool winding is bad. Could also be a relay issue.
 
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Old 05-08-18, 08:05 PM
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Thanks for the response. No furnace, the system has a heat pump. I can trace the wiring and make sure all connections are secure, how would I determine if is a winding issue?
 
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Old 05-09-18, 04:27 AM
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If you can find a wiring diagram/schematic of the air handler, you can determine if the motor has multiple windings (for different speeds). Assuming it does, you can check the motor windings with an ohmmeter. Alternatively, there may be a label on the blower motor that shows the connections for the windings. Disconnect the motor before measuring the resistance of the windings.
 
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Old 05-09-18, 05:04 AM
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Check for high voltage to the motor in both cooling and heating modes. If there’s voltage in cooling ring out the windings on the speed used for cooling.
You’ll need your meter to do this of course.
 
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Old 05-14-18, 04:42 PM
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I checked the connections and one of them was bad. I stripped the wires back and reconnected. It worked normally so I thought the problem was solved. It was cool for a few days so I didn't have to run it. Yesterday was warmer, it started off ok but after a while it started switching on and off, even though the outside unit stayed on. I checked the connection again and the connection was bad again, it looked burnt. does that mean the windings are bad on one speed and drawing too much power?
 
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Old 05-14-18, 04:46 PM
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A burned connection usually signifies a loose connection.
 
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