20valvevermont

The controls on the head unit all work fine. When I turn the fan up to 12 nothing happens. 10 min later the fan will kick on full blast. My local repair guy, who used to work at the dealer for 15 years, says I need a new blower motor. Was wondering if it works sometimes that it could be a loose connection and not the whole motor? Car has 68k miles on it.

Thanks!

Also the motor is behind the dash as it has been in every Audi I have owned. Is glove box removal easy on the B8? Seems like something I can do myself like I have when I owned 1990 20valve. Any thoughts? can't seem to find any repair manuals for the newer Audis!

Moviela

Your guy might be correct, but unless he connected VAG-COM or equal and did an examination of the encoder, the processor, the driver, and the motor he is just guessing.

The glove box is not so hard to remove. This website shows how to add a cooler duct to the glove box, and has steps to remove the box:

http://www.audienthusiasts.com/Project_GBCooler.html

We can assume the encoder works and the computer reads it. When you turn the **** the video display shows you have moved the encoder. This means the computer understood the rotation and direction of the encoder, and displayed the command on the screen. The output from the computer is sent to the driver. The driver reads the bits and does PWM (Pulse Width Modulation) conversion. The driver can fail, but usually the motor does not move or is always full blast, or fixed at some intermediate speed.

Does the motor work properly at other speeds? After the motor starts after half an hour does it ever stop by itself?

It could be a bad connection, and using a laptop to chat on the CANbus you can test the players individually and wiggle connectors to see who might be the troublemaker.

20valvevermont

It comes on and off in waves when its on then just shuts itself off then comes back on. The first time it kicked on when it wasn't working I had made a hard left turn so I was thinking it could be a loose connection. Thanks for all the help I really appreciate it!

he also did hook up the computer to it and it had 2 fault codes but not specifically the blower motor. Some other tech was doing it and asking my buddy and he just said yup blower motor.

Morne Van der westhuizen

Sorry to necro a dead thread but ive been having a similar issue,i have a 2011 a4 b8 model ,ive ruled out the blower motor and possibly the resistor , the resistor gets a constant 10ish volts on the thin wire but the main "THICK" wire + gets no voltage at all, after scouring the web for help yours is the only post that mentions another part above the resistor you refer to it as a "driver" ,is this something that i could test ,is there a specific fuse / relay for this that i can check?

thanks in advance

SMac770

The wiring layout for the V2 fresh air blower motor and the J126 fresh air blower control module (ie, the resistor) shows five wires to the J126. Two are the plug to the blower motor. Three are in a 6-pin plug:
pin 1, purple, LIN bus to the J255 climate control module
pin 3, brown, ground to central tunnel ground point
pin 4, red/blue, 12v from fuse panel D, row 2, fuse 8

So if you're measuring no 12v on the red/blue wire, check the fuse. Fuse panel D is the right end of the dash, should be two columns of fuses. Row/column 2 should be the forward/right one, fuse 8 should be a 40 amp. The power source to row 2 is term 30, so always on. Use a multimeter to check the voltage to ground on both test pads on the fuse. Both should be 12v at all times, ignition on or not. But if only one is 12v, then your fuse is not passing 12v and its blown.

Morne Van der westhuizen

I have repeatedly checked all fuses labeled as either "A/C or blower" or anything to do with climate control ,unfortunately all the fuses are ok so the fault lies elsewhere ,what is the "Driver" you spoke of, is it a physical unit similar to the resistor or part of the infotainment / climate cluster?

thanks for assisting me with this as i'm at whits end, owned the car for 15 days and now im getting all these fault's to which the dealer just says "it worked when we sold it to you so its not our problem", welcome to South Africa'n logic i suppose.

SMac770

Don't know what this other person is referring to by "driver". He's likely talking about the LIN, which tells the "resistor" the amount of activation of the blower fan.
Thin and thick are not colors. Refer to the colors when saying what voltage is being measured on what wire. Though it's clear the thin wire is going to be the comm line and the thick wire is going to be the power line. Though I hope by thick wire you're not referring to the brown wire.
You said there's no 12v on the blue/red wire, yes or no? "all the fuses" is not relevant, in this instance there is only fuse 8, 40 amp, in column 2 in panel D, right end of dash. If that's showing 12v on both sides, then there's a problem with the wire and its very short run from the fuse block to the "resistor".