A/C fan not consistently running

AKEPLER

MEMBER
2012 AUDI A4
2.0L
4 CYL
TURBO
4WD
AUTOMATIC
68,000 MILES

Car listed above is the Avant model. My A/C (heat or cool) is inconsistently coming on when required. When the fan comes on you can hear and feel it going in and out sometimes. I’m wondering if this is more likely the fan or the resistor which controls the fan. I took the glove box out to see the assembly and fiddled around with the wires and parts with car running and after doing that it ran well for 4 days, the 5th day it’s back to intermittent operation. There appears to be no rhyme or reason as to when it comes on or shuts off.

Friday, June 19th, 2020 AT 10:29 AM

3 Replies

KASEKENNY

MECHANIC
18,907 POSTS

When you say A/C fan, are you talking about the A/C condenser fan in the engine compartment or the blower fan inside the passenger compartment that blows the air on you?

Clearly this is going to make a difference on the info I provide however, the theory is going to be the same which I think you are correct. It is either the relay or motor in my opinion.

Let me know which fan and we can get you the info on it. However, the way to test this is to check voltage at the fan when it should be on. If you have 12 volts then it is the motor if the fan is not on. If not, then you have a control issue.

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Friday, June 19th, 2020 AT 4:55 PM

AKEPLER

MEMBER
2 POSTS

I’m specifically speaking about they blower in the car right behind glove box. You can hear it go in and out from time to time while it’s running and then sometimes it doesn’t come on at all.

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Friday, June 19th, 2020 AT 6:54 PM

KASEKENNY

MECHANIC
18,907 POSTS

Okay. This may be a control module issue or the fan motor. The only way to know is check voltage on each of these wires at the motor when it is acting up. Let me know if you have questions about this but if you have constant voltage when it is acting up then it is the motor. If the voltage is dropping and rising with the blower motor then it is a control module issue.

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