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Mustangfreak

HVAC Blower not blowing all the time

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I have a 2010 MKX and the HVAC system is acting up. With the controls set to max fan speed, sometimes it'll blow hard, and then sometimes itll blow so soft you can't tell. And then sometimes it will not blow at all. And it seems that the hotter it is outside, or the longer the car is driven, the weaker it'll blow over time.

 

It's really a gamble when it comes to this. Some days it'll work, and other days like today it won't work at all.

 

Is it the blower motor resistor? The blower motor itself?

 

Can I jerry rig this system to work until I can afford to buy new parts?

 

 

Thanks guys.

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I had this happen before finally the fan motor gave out. Not to say this still couldn't be the resistor, though, that's the difficult part. The TYC fan motor from Amazon or RockAuto is a fairly low-priced DIY-install part. A bit noisier than Motorcraft, but apparently blows more air as well.

 

I remember at least one person having the resistor being the issue, seach the forum for "blower resistor", should get a hit.

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I had this happen before finally the fan motor gave out. Not to say this still couldn't be the resistor, though, that's the difficult part. The TYC fan motor from Amazon or RockAuto is a fairly low-priced DIY-install part. A bit noisier than Motorcraft, but apparently blows more air as well.

 

I remember at least one person having the resistor being the issue, seach the forum for "blower resistor", should get a hit.

I did a search at first and not everyones symptoms were the exact same as mine, so I thought I'd make a post as well.

 

I called my aftermarket warranty company and they said the control module and blower fan were covered, but the resistor is not. So I think I'm gonna replace the resistor myself, and if that doesn't fix it I'll take it to the dealership.

 

Edit: After seeing the TYC price on Rock auto, its not worth it to take it to the dealer. I have a $100 deductible, so I'd be wasting money.

Edited by Mustangfreak

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Isn't the resistor completely out of the circuit when the blower is set to high? The HVAC Control Module decides whether to pass current through each leg of the resistor or go direct to the motor.

Edited by enigma-2

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I would be curious what you figured out on this, my Ford Edge seems to have the same behavior. I was testing yesterday to see if maybe the evaporator core was freezing up due to low freon. I was driving across LA and back and here's my preliminary testing. If I turned the temperature as LOW as it would go, and the fan on HIGH, within about 20 minutes the air flow got slower and slower to the point it was barely moving air. Then I turned the AC OFF and the fan OFF. Drove 15 minutes and turned fan back ON and temp to LOWEST and it worked great again.

 

So to test if that was from a frozen evaporator (which would act like that more or less), I then kept the fan on HIGH, but turned the AC to about 78 instead of 60. Drove for 40 minutes with no issues. Slowly lowered temperature to around 72 and the fan still kept blowing full speed. So, in my case I'm suspicious that the evaporator core is freezing due to low freon. I'm going to see if there is a way to get a visual on the evaporator to confirm.

 

I'd be interested to know what your fix ends up being.

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I would be curious what you figured out on this, my Ford Edge seems to have the same behavior. I was testing yesterday to see if maybe the evaporator core was freezing up due to low freon. I was driving across LA and back and here's my preliminary testing. If I turned the temperature as LOW as it would go, and the fan on HIGH, within about 20 minutes the air flow got slower and slower to the point it was barely moving air. Then I turned the AC OFF and the fan OFF. Drove 15 minutes and turned fan back ON and temp to LOWEST and it worked great again.

 

So to test if that was from a frozen evaporator (which would act like that more or less), I then kept the fan on HIGH, but turned the AC to about 78 instead of 60. Drove for 40 minutes with no issues. Slowly lowered temperature to around 72 and the fan still kept blowing full speed. So, in my case I'm suspicious that the evaporator core is freezing due to low freon. I'm going to see if there is a way to get a visual on the evaporator to confirm.

 

I'd be interested to know what your fix ends up being.

I'm going to try this and report back as well.

 

Is refilling the freon easy on these cars?

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Low pressure side is buried on the left side (passenger) all the way under the air intake cowling. Really hard to connect to.

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I would be curious what you figured out on this, my Ford Edge seems to have the same behavior. I was testing yesterday to see if maybe the evaporator core was freezing up due to low freon. I was driving across LA and back and here's my preliminary testing. If I turned the temperature as LOW as it would go, and the fan on HIGH, within about 20 minutes the air flow got slower and slower to the point it was barely moving air. Then I turned the AC OFF and the fan OFF. Drove 15 minutes and turned fan back ON and temp to LOWEST and it worked great again.

 

So to test if that was from a frozen evaporator (which would act like that more or less), I then kept the fan on HIGH, but turned the AC to about 78 instead of 60. Drove for 40 minutes with no issues. Slowly lowered temperature to around 72 and the fan still kept blowing full speed. So, in my case I'm suspicious that the evaporator core is freezing due to low freon. I'm going to see if there is a way to get a visual on the evaporator to confirm.

 

I'd be interested to know what your fix ends up being.

This did not work.

 

Right now the fan is not blowing at all, and its 95* avg right now during the day. :(

 

Before when it would work a little bit, it seemed that the hotter it was outside, the worse the problem was. We had a couple of days of rain, and it got down to 85, and even down to 80 and the fan worked great and wouldn't slow down.

 

Is it the resistor for sure now? Or something else?

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just replaced the resistor and it started working, at half speed again. Get home and its barely blowing. Just went out to check the filter, and now it doesnt work at all.

 

What the heck. I'm sick of this problem. What could be wrong now

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i am similar problem. 2011 edge. BLower cycles on and off. on for 5 sec off for 2 secs. replaced resistor but no change

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