Climate control works at times

[Gocaudi]

Hello I've spent the last hour searching but haven't found a thing. I have a 99 a4 avant and my heater control only works at time the fan indicator will go up and down but my a/c or heater wont work. It goes on when it wants and when it does turn on the a/c will blow cold and heater hot, the fans will blow strong and ill be able to control the speed for a moment before it decides to turn off. Need help plz as winter approaches i dont want to be without heater

[Gocaudi]

Update I removed my glove box and tested for power its turns out the harness is faulty and will be changing it next weekend

[DeeInSeatown]

Update I removed my glove box and tested for power its turns out the harness is faulty and will be changing it next weekend

Did this work? Have the same thing going on with my 99 A4, except the fan doesn't come on at all.

[DeeInSeatown]

Anyone with input on this? Just ran a fault code test and got 01273 - Fresh Air Blower, 17-10 - Control Difference (Intermittent). Not entirely sure where to go from there.

[DeeInSeatown]

Anyone? Just pulled the blower motor. Getting 12v to the controller, and 12v on the output from the controller when the fan speed is cranked to max. The motor still won't turn when the controller is hooked to the motor and there's no friction or noise on the motor bearings. Electrical resistance seems fine on the motor too (less 0.1 ohm).

[warrenzo]

I had this problem when a bunch of my wires shorted out on my radiator. There's a harness leading to the rad fan on the passenger side, and it was intermittent until the fuse blew and I knew something was up and chased down the short.

I'd guess there's a short somewhere else, could that be a possibility?

If it gets 12v to the fan, make sure it's constant. Also check the fan motor. You'll just have to track it by elimination. Good luck

[DeeInSeatown]

I had this problem when a bunch of my wires shorted out on my radiator. There's a harness leading to the rad fan on the passenger side, and it was intermittent until the fuse blew and I knew something was up and chased down the short.

I'd guess there's a short somewhere else, could that be a possibility?

If it gets 12v to the fan, make sure it's constant. Also check the fan motor. You'll just have to track it by elimination. Good luck

I was able to check the input and output power from the blower motor control unit mounted to the fan. When the climate control was turned up to full speed the output wires to the blower motor were at battery voltage. Made me think blower motor but the part of the plastic connector where the high current wires attached to the input side of the controller were partially melted. That made me suspicious of the controller, and that sounds like a fairly common failure point. After I pulled the blower motor I was able to hook it up straight to a battery and confirm the motor worked.

Was able to find some aftermarket parts for decent prices but they all have a two pole connector from the controller to the fan that the factory part doesn't have. Mine has the wires to the motor hardwired to the controller. I even tried calling a VW/Audi dealership to see if they had a part number for that 2 pole connector on other models that share the controller. They weren't able to find that 2 pole connector and every controller sounds like it was the same as what I pulled out of my card.

So just bought a new blower motor/controller unit even though I'm pretty sure it was just a controller failure. Will report back when the new part gets in.

[NicksAEB]

When mine was acting crazy it was because the buttons were all gunked up behind them. Took it apart and cleaned with soapy water and or alcohol. I forget which. Works fine ever since. Thanks Audi for the stupid cup holder design!