IT_S8 Posted May 19, 2008 Report Share Posted May 19, 2008 From time to time we find out questionably interesting things during our core business which we feel a pressing need to share with someone. The wifes not interested, and the kids dont understand so its your turn For those that own Vagcom, or the shareware equivalents, you have a feature called measuring blocks. This lets you connect to a particular controller and view what information it knows. For example, the Engine ECU knows engine speed, timing, temperatures, the navigation can tell you what wires / aerials are connected and the instrument cluster can tell you everything from fuel level in litres to current battery voltage - but - the HVAC (Heating Ventilation and Air Conditioning) takes the prize for the largest number of misc bits of info. Lots of different flaps, with degress of rotation, temperatures of coolant, airways, vents and other a/c related items. So, it was a curiosity when we discovered that the HVAC unit has an input to know when you are washing your windows. Not wiping, but actually when you have the squirter spraying water. What can i say, it was a long trip to Billing yesterday and with time to kill a session with Vagcom commenced. After a number of theorys had exhausted, we proved without a doubt that the HVAC unit uses this information to automatically switch your ventiliation onto recirc mode whilst the jets are being operated. How long, depends on your settings. If you have the Climate module on Auto-Recirc anyway, then it will spend 2 minutes on recirc after squirting. If you have it on fresh air only, the it will recirc for 20 seconds. This was done on a Post facelift car, but it wouldn't suprise me if its the same for preface. We're not 100% why they did this. We doubt its for water ingress, so our only theory is that it was done to stop the smell of the sreenwash from entering the cabin ? Its very effective - once we discovered this we realised we've never smelled the screenwash whilst in an A8 - and you never will. So, bin the expensive posh fruity fragrance as it can only be enjoyed by the folks behind you... Another money saving tip from A8 Parts.... Quote Link to comment Share on other sites More sharing options...
rottenbend Posted May 19, 2008 Report Share Posted May 19, 2008 I've heard this before about the Phaeton. Apparently Dr. Piech specifically asked for this feature! As you say - seems like over engineering to me. Quote Link to comment Share on other sites More sharing options...
cruiser647 Posted May 19, 2008 Report Share Posted May 19, 2008 I love the smell of screen wash in the morning! (and any other time of the day too). Trying to think back to my A8, and I cannot remember smelling or not smelling the screen wash. Mine was a '97 QS. What a spoil sport. Won't buy another unless that 'feature' can be disabled! Quote Link to comment Share on other sites More sharing options...
Botang Posted May 19, 2008 Report Share Posted May 19, 2008 My mate is a HVAC engineer so I'll ask if its a common thing. Quote Link to comment Share on other sites More sharing options...
Ska Posted May 19, 2008 Report Share Posted May 19, 2008 Nice info Ian, but I can't believe you lot use screen wash:eek:! Think of your paint for God's sake! Quote Link to comment Share on other sites More sharing options...
IT_S8 Posted May 19, 2008 Author Report Share Posted May 19, 2008 Well, in theory the screenwash should be aiming at your glass, not your paint... :-) Whats recommended instead then just out of curiosity ? Quote Link to comment Share on other sites More sharing options...
Ska Posted May 19, 2008 Report Share Posted May 19, 2008 When the notoriously fiddly connector pipe is secure, the jets are pretty powerful so the water ends up on the roof and the side panels. I don't know if there is a paint friendly screen wash but I just keep the glass squeeky clean by claying it regularly to remove contaminants and clean the wiper blades so all I need is water when the birds do thier thing. Quote Link to comment Share on other sites More sharing options...
jettadeluxe Posted May 20, 2008 Report Share Posted May 20, 2008 My A8 stank of screenwash if used, so I'm guessing it wasn't programmed on pre-facelift. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.