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AC Problem (only blowing cold air on driver’s side)
I was hoping someone might have a little insight into what issue I’m experiencing right now. My 2013 S8 has only been blowing cold air on the drivers side front and back, and then on the passenger side front and back it’s just the blower blowing warm air. Fortunately the drivers side blows cold enough that it cools the car off after awhile but summertime in Georgia is not the time you want your AC underperforming. I took it to a local shop and had the code pulled 0137 - motor for right side window defrost flap - B10D8 22 [008] - signal amplitude too high
The guy at the shop (just a small local place that works on German cars) said he wasn’t too familiar with this issue and didn’t have the time to figure it out with the workload he had. Anybody else have this issue before? Did it require taking the whole dash apart to access the defrost motor or is there a simpler fix floating around out there?
Probably not easy, and no magic click the ruby shoes three times short cuts.
1. First suggestion as a bandaid: actually clear the code and see what happens. May well come back, but worth trying. When you reset some codes, it can clear a fail safe that prevents things from operating normally, at least until it sets off the code again.
2. A lot of HVAC stuff has now gotten to where at least you don't have to pull the whole unit out of the dashboard and under hood in plenum area, which was a nightmare. But you still have to do some disassembly and know what you are doing. Or more likely, a shop who knows it. Needs to be someone pretty dedicated to Audi and VW late models and/or manual in hand, not 20 year old A4's and Golf wing it stuff. Might realistically mean dealer if you don't have good DIY skills and VCDS, or find an indy with a mechanic/technician who worked at a dealer within the last decade.
3. Realistically you may need a shop manual, in that I'm suspicious of the code relative to the issues described. The code suggests a pretty narrow module, while the symptoms seem much more generalized to the system overall.
4. Pages below for this narrow area. If you need more, you should get the manual. Pretty much you would need to...notice it talks about configuring it toward the end ("basic settings"). That in turn basically means either shop equipment or VCDS.
5. Your symptoms suggest to me it may be whole side, given you say it doesn't cool there. Thus the code may be misleading. Yes, per the code you probably have an issue of some sort with one (minor) flap, but that doesn't explain right side and rear running consistently warm to me.
6. If it were mine, I would be looking at the heater control valve, wherever that is buried on a D4. With an HVAC system, the heater/hot water flow is of course integrated. If that valve is not closing wellon the passenger side, you can get the heating and the A/C flows fighting each other. A further guess is the driver's side may be by itself on that valve with the rest of car (including rear) on other part. On a D3, I know from taking it out it had basically two circuits even with four seat/rear controls. Also I doubt there is really a way to check that valve function with code reading, so you have to go more by symptoms and old school diagnostics--feeling hoses (or heat gun), pulling lines, etc. From experience, that would be true of the D3 one. On D3 it was in the plenum area behind engine (under hood). Likely true on D4, as opposed to under dash. I am also guessing that like D3 there is really only one main A/C cooling panel in the unit to generate the cold air, along with the two heating panels the D3 had. Then the flap controls mix and match within reason for the temperature and vent output settings, or decide how to set them on full Auto.
I replaced an interior trim piece on my 2016 S8 a couple of days ago. In order to get to the appropriate screws, I had to remove the glove box. While laying upside down (looking up into the underside of the dash) I notice the part mentioned above. It really isn’t that hard to get to. Once the glove box is out, you can’t miss it. I used this video to guide me through the process. All you need to watch is the part about the glove box removal.
My D4 has almost the same code (has been there for more than one year, always comes back immediately after clearing):
0137 - Motor for Right Side Window Defrost Flap - B10D8 22 009 - Open or Short to Ground.
Only symptom noticed is that sometimes after car is started some motor noise is heard from the passenger side behind glove box for around 5 seconds. Then silence for around 1 minute and then the same noise again. Then silence for the rest of the ride.
Had the same problem on my A6 with the heat being only on one side and faint. They had to flush the heating system and finally replaced the entire radiator because the fluid in the system was too dirty, they never got it working as new because it was too blocked up. The pipes in the cabin are smaller than at the radiator so you can have a working radiator and fluid not able to go through the smaller pipes in the cabin. Mine was clocked and that means that it works half way through and then starts not working. Not sure if the airconditioning works in the same way but I think everyone should clean the fluid once in a while before it clocks up and gets expensive to replace. Let me know what you find out...
I removed the glove box to check and the correct part is 4H0820511B. Some googling around revealed the problem might not be the motor but the HVAC Duct Adapter (Front), part number 4H1819354B. But since there are no symptoms, perhaps I will just leave the whole thing as it is. Heat and cold are working properly.
06-27-2020, 05:54 AM
AC Problem (only blowing cold air on driver’s side)
