Heating Stuck On / Busy Actuators - Do I need VAGCOM/VCDS?

[ck_uk]

Hi All

My first posting here, hoping to get some advice please. 

We have a 2003 A4 Avant which has developed an issue whereby the heating is on all the time. Hoping to try and resolve before the summer hits!

I've removed the glovebox and, even with the heating controls switched OFF on the dash, you can both hear and see the actuators trying to move. 

I've disengaged each of these in turn from the control arms just to make sure the arms are not seized. 

The flap over the main blower vent on the leftmost side, is at a 45 degree tilt. This doesn't change regardless of whether LO or HI selected when operating the system temperature. 

It seems to me that it could be an issue with whatever sends the control signals to the actuators, as they all seem to be trying to work at the same time.

My question is what next? Do I need VAGCOM diagnostics to see if there are any codes from the HVAC part of the system? I can only assume that even a decent OBD2 reader such as a Foxwell NT301 will not be able to read the codes from the HVAC?

Has the system got confused at some point, and needs a reset? 

It's notable that, with the ignition ON and the heating controls OFF, these actuator sounds can be heard every second for several minutes before the system goes silent.

Thanks in advance for any help

 

[LarHal]

There are 3 actuators that control the air flow. They have sensors in them which tells the control module their position. The sounds you are hearing are the actuators cycling and trying to sence their position which they cant. So they remain open and allow the hot air to come in. VCDSS would tell you which one is at fault, in any ways they have to be replaced. Items 4, 6 or 7

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To the begining

Air-conditioning system with electronic regulation for Audi A4/Avant(A4) 2002 [EUROPA]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

		№	part number	description	remark	unit	model
				Air-conditioning system with electronic regulation
		1	8E1 820 021 E	Fan	lhd	1
		1	8E2 820 021 E	Fan	rhd	1
		2	8E1 820 511 F	actuator motor for air flow flap	lhd light blue V71	1
		3	8E1 820 511 D	positioning motor for recirculated air operation	lhd blue V 113	1
		3	8E2 820 511 D	positioning motor for recirculated air operation	rhd blue V 113	1
		4	8E1 820 511 B	Servomotor for defroster flap	lhd green V 107	1
		4	8E2 820 511 B	Servomotor for defroster flap	rhd green V 107	1
		5	8E1 820 511 G	control motor for temperature regulating flap	left lhd red V 158	1
		5	8E2 820 511 E	control motor for temperature regulating flap	right rhd yellow V 159	1
		6	8E1 820 511 K	actuator motor, footwell flap foot well flap	lhd white V 70	1
		6	8E2 820 511 H	actuator motor, footwell flap foot well flap	rhd black V 70	1
		7	8E1 820 511 H	control motor for temperature regulating flap	right lhd violet V 159	1
		7	8E2 820 511 F	control motor for temperature regulating flap	left rhd brown V 158	1
		8	8E1 820 353 B	Air distribution housing	lhd	1
		8	8E2 820 353 B	Air distribution housing	rhd	1
		9	8E2 820 024	Evaporator housing	rhd	1
		9	8E1 820 024	Evaporator housing	lhd	1
		10	8E1 820 153	Intake duct	lhd	1
		10	8E2 820 153	Intake duct	rhd	1
		11	8E1 819 151	Footwell vent	lhd	1
		11	8E2 819 151	Footwell vent	rhd	1
		15	8E1 820 103	evaporator F >> 8E-3-285 000*	lhd	1
		15	8E1 820 103 A	evaporator F 8E-3-285 001>>*	lhd	1
		15	8E2 820 103	evaporator F >> 8E-3-285 000*	rhd	1
		15	8E2 820 103 A	evaporator F 8E-3-285 001>>*	rhd	1
		16	8E1 820 031	heat exchanger also use:	lhd 8E0 898 380	1, 1
		16	8E2 820 031	heat exchanger also use:	rhd 8E0 898 380	1, 1
		17	4B1 819 011	Auxiliary heater for air conditioner	LLKG Z35	1
		17	4B2 819 011	Auxiliary heater for air conditioner	RLKG Z35	1
		20	8E0 898 380	Gasket set		1
		21	8E1 898 350	1 set: pipes for heat exchanger also use:	lhd 8E0 898 380	1, , 1
		21	8E2 898 350	1 set: pipes for heat exchanger also use:	rhd 8E0 898 380	1, , 1
		23	8E0 820 992 A	Bungs		1
		24	8E1 816 311	air hose for models with cool box	lhd	1
		24	8E2 816 311	air hose for models with cool box	rhd	1
		-	8E0 820 701	Vent for vehicles with air condit. Glove compartment		1
			8E0 820 701 4 PK	soul (black)
		25	1K0 907 543 A	Temperature sensor	G 263	1
		26	N10 424 101	hexagon head panel screw	4X16	X
		28	4B0 820 539	Temperature sensor	G 262	1
		29	4B0 820 539	Temperature sensor	G 261	1
		30	8E1 260 113 A	water drain pipe	lhd	1
		30	8E2 260 113 A	water drain pipe	rhd	1
		34	8E0 260 155	drain tube		1
		37	8E1 819 079	Retaining bar	lhd	1
		37	8E2 819 079	Retaining bar	rhd	1
		38	N01 028 73	Hexagon bolt	M6X16	4
		39	N90 457 003	hexagon head bolt (combi)	M6POWX15, 5-S1	1
		40	8E0 820 539	Temperature sensor evaporator	G89	1
		41		Discont. / replace:	8E1 898 400 8E2 898 400	1, 1	lhd rhd
		42		Discont. / replace:	8E1 898 400 8E2 898 400	1, 1	lhd rhd
		43		Discont. / replace:	8E1 898 400 8E2 898 400	1, 1	lhd rhd
		44	8E1 898 400	1 set attachment parts for heat exchanger	lhd	1
		44	8E2 898 400	1 set attachment parts for heat exchanger	rhd	1
		45	N10 095 101	Clamp	8X17	1
		47	4B1 819 164	Cover for models without auxiliary heater	lhd	1
		47	4B2 819 164	Cover for models without auxiliary heater	RLKG	1
		-	8E0 819 425 B	Cover cap		1
		-	8E1 898 001 B	1 set: levers for air distribution housing	lhd	1
		-	8E2 898 001 B	1 set: levers for air distribution housing	rhd	1
		-	8E0 898 001	1 set: levers for air distribution housing Defroster flap F >> 8E-4-280 000*		1
		-	8E0 898 001 A	1 set: levers for air distribution housing Defroster flap F 8E-4-280 001>>*		1

 

[LarHal]

Correction. 4, 5, or 8

[ck_uk]

On 2/25/2025 at 7:06 AM, LarHal said:

Correction. 4, 5, or 8

Thanks Larry for the great info, really appreciated!

Since it seems to be all of the sensors making the sound, would that suggest that there could actually be a problem at the Control Module end? 
Like you say, VCDS would prove for sure. I'd have to find a dealer to scan the system for me.


 

[LarHal]

No it won’t be the controller. It will be a specific motor. 

[LarHal]

The motor has the sensor built in. Maybe there is someone near you with VCDS who could scan your car which would give you all the fault codes and would identify the faulty unit. I have VCDS and it is the most useful tool I owne.