Right AC vents blow warm, left AC vents blow cold

[MrNomad105]

2016 VW Golf Sportwagen. TSI. Back in Jan 2025, VCDS issued 329220 - Motor for Air Distribution Flap code. No other codes.

Problem: with the AC on full, coldest position, the volume of air out of all 4 AC vents is correct. The issue is the air coming out of the right vent above the radio, and the air coming out of passenger vent are warmer than the driver's vent and the left vent over the radio.

All of the other positions HEATER, DEFROST, ETC., operate OK. The only issue is the air coming out of the right 2 vents is warmer than the air coming out of the left two vents in the AC position.

I cleared the error, used Basic Setting, IDE01546 Adapt Door End Stops, and the temp at the right vents got colder. 30 minutes later, the problem reoccurred.

VCDS issued no code.

Air flow seems normal. IOW, air is blowing, but vents 3 & 4 are not as cold as vents 1 (driver) & 2 (left vent above radio).

I removed the motor located above the gas pedal. Is that the correct motor for this problem?

I reran "Adapt Door End Stops" with the wires connected to that motor. The motor was hanging down. I watched the motor go back and forth with no issues or noises. Motor looks & sounds good to me.

Comments and suggestions welcome.

 

[Dr Sheldon]

Back in Jan 2025, VCDS issued 329220 - Motor for Air Distribution Flap code.

Did you resolve that by doing some actual work to the car or just ignored it then hoped it would fix itself ?

 

[MrNomad105]

It always saddens me that some people prefer to impugn their fellows rather than be helpful. Yes, I reset the code in January, it worked, and I hoped that would be the end of it, but apparently not. The car has standard AC, btw, not Climate Control. I confirmed that this motor performs the blend and although it operates quietly when it's not installed, when there is a load on it (IE, the flap), it may skip a gear internally which explains the clicking these motors frequently emit. Given how difficult it is to dismantle the flap system, replacing the motor seems like a logical first step. I'd suggest to anyone else attempting this work to purchase a 1/4" box wrench ratchet to make removal and installation of the two screws much easier. Remove the top screw first. The connector disconnects easily with a small straight blade screwdriver.

I may machine a matching gear and use it to operate the flap manually to confirm that the flap CAN close, that there are no obstacles impeding its movement. Another forum member suggested bypassing the heater core so that hot coolant no longer heats the heater core and warms the air passing over it, but that would reduce the overall amount of coolant in the system which is not advantageous during summer heat. My aviation experience compels me to do everything possible to dispel heat from an engine, not add to it.

BTW, I found a nice diagram of the system here.

AIR CONDITIONER & HEATER. EVAPORATOR & HEATER COMPONENTS.. 2016 Volkswagen Golf

2016 Volkswagen Golf AIR CONDITIONER & HEATER. EVAPORATOR & HEATER COMPONENTS. W/O climate control. Air recirculation. Air temp regulation. Defrost door. Johnson. Mes. W/AUX heater. W/O aux heater. W/O e-golf.

parts.vw.com

Helpful suggestions and comments r welcome. Thx Dr. Sheldon.

 

[Ziddywerks]

Simple solution to your issue. I would check and of replace the affected flap motor first. Secondly It could be a low charge in the AC system. I suppose you may have a leak somewhere. I don't want to say this is common but the fact that you have warmer air between vents with AC on has direct correlation to a leak or low charge in the ac system. The usual scenario is the vents get gradually warmer from left to right this can be verified using a thermometer. Believe me I have experienced this myself on both vw and audi vehicles. I would recharge and put dye in. That is all.

 

[MrNomad105]

Thank you so much for that idea. That was the first thing I considered so I used VCDS to determine the HVAC Adv Measuring Value BAR when cold and after driving. According to the BAR, the charge is correct. Fortunately, I own a 2015 VW also so BAR comparisons are easy. Nevertheless, I will double check my work. The VCDS 329220 code I got in Jan says something may be wrong. Meanwhile, the ratching 1/4" box wrench is on order so I have time to think, test and plan. The AC still works (marginally) w/o the motor installed.

I sincerely appreciate the helpful suggestion. Hope I can return the favor in the future.

 

[Mari]

... many Golf have problems with the flaps left and right... In my previous car they had to be replaced...

 

[MrNomad105]

Simple solution to your issue. I would check and of replace the affected flap motor first. Secondly It could be a low charge in the AC system. I suppose you may have a leak somewhere. I don't want to say this is common but the fact that you have warmer air between vents with AC on has direct correlation to a leak or low charge in the ac system. The usual scenario is the vents get gradually warmer from left to right this can be verified using a thermometer. Believe me I have experienced this myself on both vw and audi vehicles. I would recharge and put dye in. That is all.

YOU WERE RIGHT! Low on gas. I used BAR, weight and gauges to add freon. I was distracted by the difference in temp and mistakenly chased after vent issues. Yes, I will add dye and try to find the leak. Thank you so much!

So why were the left vents cooler than the right? My theory... the decreased capacity of R134a probably cooled some portion of the evaporator but not all of the evap. The left two vents (apparently) draw air from that portion of the evap which was cool. Once the evap had enough gas, all 4 vents leveled off in temp.

 

[Ziddywerks]

YOU WERE RIGHT! Low on gas. I used BAR, weight and gauges to add freon. I was distracted by the difference in temp and mistakenly chased after vent issues. Yes, I will add dye and try to find the leak. Thank you so much!

So why were the left vents cooler than the right? My theory... the decreased capacity of R134a probably cooled some portion of the evaporator but not all of the evap. The left two vents (apparently) draw air from that portion of the evap which was cool. Once the evap had enough gas, all 4 vents leveled off in temp.

Knowledge is one thing, experience is another. Many have the knowledge and think they know everything but without experience that knowledge most of the time is not enough. Note this statement is not referenced to you or anyone else in this thread in any way shape or form but rather to some other knowledgeable people here that like to run their mouth and talk shit and insult others instead of actually helping and contributing to this community. Glad you got it sorted out.

In regards to your question about why is one side colder than the other:

• A low refrigerant charge can cause only part of the evaporator to cool, resulting in one side blowing cold air while the other blows hot.
  
  
• The side closest to the refrigerant line entering the evaporator is likely to blow cold air.

 

[MrNomad105]

I agree. "others instead of actually helping and contributing to this community". I flew a single engine airplane I built in my garage (with a lotta help from my friends). The goal was safety, especially when your wife or grandson was sitting next to you. As a community, we were laser focused on helping one another versus competition. Cooperation was a given. I recall an instance when a good friend damaged a flap while visiting. To get home, we took the flap off my airplane (same make and model) & installed it on his so he could get home. Two weeks later he drove my flap back to me and picked up his broken one.

As a community, aviation folks were amazing. Once again, thx for your help.

What do you think of this kit to insert some dye into the system?

Amazon.com: R134A R1234YF AC Oil Injector Tool AC Dye Injector Kit with R134a Adjustable Quick Coupler, R1234YF Quick Coupler and 2 Oil Checkers, AC Oil Dye Injector Kit for R134A R1234YF Refrigerant System : Automotive

Buy R134A R1234YF AC Oil Injector Tool AC Dye Injector Kit with R134a Adjustable Quick Coupler, R1234YF Quick Coupler and 2 Oil Checkers, AC Oil Dye Injector Kit for R134A R1234YF Refrigerant System: Air Conditioning Line Repair Tools - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

[Ziddywerks]

I agree. "others instead of actually helping and contributing to this community". I flew a single engine airplane I built in my garage (with a lotta help from my friends). The goal was safety, especially when your wife or grandson was sitting next to you. As a community, we were laser focused on helping one another versus competition. Cooperation was a given. I recall an instance when a good friend damaged a flap while visiting. To get home, we took the flap off my airplane (same make and model) & installed it on his so he could get home. Two weeks later he drove my flap back to me and picked up his broken one.

As a community, aviation folks were amazing. Once again, thx for your help.

What do you think of this kit to insert some dye into the system?

Amazon.com: R134A R1234YF AC Oil Injector Tool AC Dye Injector Kit with R134a Adjustable Quick Coupler, R1234YF Quick Coupler and 2 Oil Checkers, AC Oil Dye Injector Kit for R134A R1234YF Refrigerant System : Automotive

Buy R134A R1234YF AC Oil Injector Tool AC Dye Injector Kit with R134a Adjustable Quick Coupler, R1234YF Quick Coupler and 2 Oil Checkers, AC Oil Dye Injector Kit for R134A R1234YF Refrigerant System: Air Conditioning Line Repair Tools - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

I don't really like china specials honestly, but I understand not everyone runs a business with equipment. As long as the fitting has good engagement its worth a try. Note usually I put the system in a vacuum and add dye and freon.