Greetings:


"New to me" A8 has rear defroster dash switch which activates rear grid correctly but will not turn off manually with repeated pushes, nor after 10 minute wait...only deactivates with turning off key. Any help here...?...is timer located in switch, how does one remove switch from central dash panel, noticed red LED does not light(only yellow triangle)???

Thanks,

Craig

 

Installing the Switch to Toggle Inputs
A new switch must be installed to toggle the inputs between the CD player and iPod inputs. You could use any maintaining two position switch, I used a front foglight switch and mounted it in the dash.
To remove the switch and gain access to the wiring, it is easiest to remove the center vents. These are removed by using the hooked dentist tools from Pro.Fit International. They can also be fabricated using instructions below. Snake them in the center vent, and engage them in the hole just behind the left and right vent control (D shown below). Use a flashlight and you'll see where they engage. It is best to have a friend help you the first time, the vent is a friction fit and in tight! Pull as hard as you can and it should slowly come out. Once it is out, disconnect the two wire connections and you'll have easy access to the switches.

Remove the blank switch by pushing it out from behind<ul><li><a href="http://www.audipages.com/Tech_Articles/electrical_equipment/ipodinstall.html">http://www.audipages.com/Tech_Articles/electrical_equipment/ipodinstall.html</a</li></ul>

 

You say that it won't toggle off when depressing it after the defroster is energized.

The switch or the relay has an electronic circuit in it for the time out function. This function is not working, neither is the toggle off function.

So when you cycle the ignition, it goes to its stable position, which is off. Then turn it back on again and it stays on.

When I went to go buy a spare front fog light switch for my iPod install, I also checked into the price of a rear defroster switch. The fog light switch was about $30, the defroster switch about $48 as I recall. Therefore, I'm going to say that the time out function is in the defroster switch. If so, a new switch should solve your problem.

Here's the schematic....as you can see, it doesn't show where each one is....J33 is the relay, E15 is the dash switch.

<img src="http://www.audipages.com/Tech_Articles/electrical_equipment/defroster1.JPG">

Now that I have studied it some more (after previewing the post a few times), it appears the time out function is in the switch. Why do you ask? Because it has two lights (the two round things with the arrows coming off them), one for the defroster indicator, and one red light when the headlights are turned on.

They receive power from the vertical line (12 VDC) in the schematic (where they go horizontailly off to the right). You can see both light bulbs, one comes on when you press the switch, the other through a ground circuit through the headlight switch (not shown, continued on another page).

See the little transitor box above the right most light bulb? That's the time out function. Based on this, I'm almost sure it's in the switch. The push button on the right is the actual dash switch button. Once the electronic circuit is energized, it picks up the main contact in the J133 relay and energizes the rear defroster.

I don't normally just go buy electrical devices to see if that is the problem without fully troubleshooting it....but if you don't have the skills to do that, spending $50 on a switch is a lot cheaper than letting anybody else try and troubleshoot it for you. They would probably not get it right the first time either unless they really knew what they were doing. I think that is hard to come by when performing electrical troubleshooting.

If you replace the switch, you'll probably fix your problem, but I won't guarantee it! <a href="http://www.audipages.com/Tech_Articles/electrical_equipment/ipodinstall.html">The iPod install instructions on audipages.com</a> shows you how to remove the dash switches.

How's that for a response????

 

Yeah, what he said......