2006 jetta tdi no heat.

Red Shed

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06
I have a 2006 tdi with 200k. Heat stopped working last week. So far I've replaced the t stat. Flushed the heater core. And checked the auxiliary heater. The heater is getting 14 volts I'm not sure if that means it's working or not. I can see the arm on the blend door move when I turn the handle. No foam coming out of the vents. New cabin air filter. Fan blows good. Thermostat reads 180. All the hoses in the engine bay get hot to the touch so I don't think it's the water pump. Any suggestions?
 

pedroYUL

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Do you have VCDS? There is a test for the Aux Heater output, which by the way gets constant voltage pretty much straight from the battery.


I bet your problem is with the Aux Heater. Search in here on how to re-solder the resistors, it works for most, it didn't work for me.


Good luck!
 

kdawg89

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Aux heater wouldn’t stop the heat from working once up to temp. Does the heat start working once the engine warms up?


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Red Shed

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Do you have VCDS? There is a test for the Aux Heater output, which by the way gets constant voltage pretty much straight from the battery.


I bet your problem is with the Aux Heater. Search in here on how to re-solder the resistors, it works for most, it didn't work for me.


Good luck!
I do not. I've seen it mentioned in other threads but no idea what it is. I'm assuming it's some kind of software that lets you communicate with the ecu. I have a laptop with a tactrix cable I use for tuning Subarus. Do you think I could make that work?

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Red Shed

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I'll also correct my previous statement. It's not like there's no heat at all. My IR thermometer says it's about 75 80 degrees. It's Luke warm but never gets good and hot. And on cold mornings (Connecticut) it just never really warms up the car before I get where I'm going. Also terrible for defogging the windshield.

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pedroYUL

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what he says ↑


How's the reverse gear switch (in a manual)? If stuck on reverse then the car will always blow the opposite direction.


VCDS is a cable and software, extremely helpful on diagnosis of VAG cars
 

Red Shed

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what he says ↑


How's the reverse gear switch (in a manual)? If stuck on reverse then the car will always blow the opposite direction.


VCDS is a cable and software, extremely helpful on diagnosis of VAG cars
wait?! what?! if the car thinks its in reverse the blower will blow backwards?
 

bbexotics

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The servos open the vents, Yes, servos are bad, that’s why vents are not opening .
 
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Red Shed

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The servos open the vents, Yes, servos are bad, that’s why vents are not opening .
which wents are you talking about? are you talking about the blend door? or some other vent? i can see the blend door arm move when i move the temp selector knob. while its moving i can hear a change in the air coming through the vents.
 

bbexotics

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Called recirculated flap motors, there are three, one for center, and one for each side. If they don’t operate properly the flap won’t open and you won’t get cold/hot air. The gears strip or brake with time.
 

pedroYUL

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wait?! what?! if the car thinks its in reverse the blower will blow backwards?

Yes, the blower blows in reverse, so fumes don't get sucked into the cabin. They started doing this with MKV gen, I assume onwards but I don't have anything newer than 2006.
 

Red Shed

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Yes, the blower blows in reverse, so fumes don't get sucked into the cabin. They started doing this with MKV gen, I assume onwards but I don't have anything newer than 2006.
ive never heard of such a thing. is there a way to test this because if feels to me that the fan is blowing air out and doesnt seem to change direction.
 

Red Shed

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Called recirculated flap motors, there are three, one for center, and one for each side. If they don’t operate properly the flap won’t open and you won’t get cold/hot air. The gears strip or brake with time.
cold air (ac) works fine in all vents. just heat does not work.
 

Red Shed

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what he says ↑


How's the reverse gear switch (in a manual)? If stuck on reverse then the car will always blow the opposite direction.


VCDS is a cable and software, extremely helpful on diagnosis of VAG cars
i Tested your theory. fan on 4. holding my hand over the vent put it into reverse no change in fan speed or direction. back up camera on the aftermarket pioneer head unit works fine so its reading the signal from the transmission fine.
 

bbexotics

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Transmission has no bearing on vents, read my post that’s your problem
 

Red Shed

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Transmission has no bearing on vents, read my post that’s your problem
which servos are you talking about? im getting air out of all of the vents. where are these servos and how do i confirm they are working or not? what are the part numbers? all of this would be useful information.
 

pedroYUL

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The vents will keep blowing when you engage reverse, but they won't draw air from outside. I'm not sure if the system goes into recirc or what, but I'm positive these cars do that so you don't get fumes in the cabin. If you listen carefully, you'll be able to tell a change in how the air sounds when you engage reverse and start moving slowly.


In any case, get help from someone with VCDS and scan your car. I bet your problem is with the Aux Heater, these things are finicky. I could get mine to heat to about 600W forcing it with VCDS, but not by itself. Lots of people are able to fix them by re-soldering the 4 resistors inside.
 

oilhammer

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There are just too many to list....
Reverse induces recirculation, that's it (Same as MAX A/C). Nothing to do with the blower.

The OP needs to determine if both heater pipes inside the car to the core are both hot, and if so, determine if the temp blend door is actually working.

VCDS will allow some easy checks, as these are electronic controlled whether or not they have actual Climatronic or not. Pretty simple system. The coolant is ALWAYS flowing through the heater core. The temp blend door just forces the air forward and through the heater core.
 

Red Shed

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i just got my new scanner in i will update you if i can learn something new. last time i checked it the 2 pipes going to the heater core were hot. one too hot to let your hand linger for more than a half second the other was warm enough to let your hand linger for a few seconds before it became uncomfortable. i can see the arm of the blend door move when i turn the knob and i can hear a change in the air as i do so.
 

Red Shed

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snan tool brought up nothing. so i said screw it and started ripping out the heater core. i have the aux heat coil on my desk as i type. anyone know how to test it with a multimeter? will update once i get the heater core out.
 

kdawg89

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Did you scan with VCDS? If you didn’t get a code for aux heater with VCDS then i would assume it is working. I think your issue has something to do with a blend door problem. I’ll bet your aux heater and heater core are hot but the door that allows the air to blow across them isn’t working correctly.


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Red Shed

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im uploading a video to youtube as i type. its not the blend door. after removing the aux heat coil you can see the blend door through the hole where it was. it looks intact you can see it operating properly. im thinking the heater core is plugged. having trouble getting the aluminum pipes going into the heater core off. this whole thing is a stupid design. you'd think they would give you enough play in the pipes to push them back out of the way or at least put a tab on them so you can push on them.
 

oilhammer

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There are just too many to list....
You did remove the screw between the two fitting on the firewall correct? Otherwise the tubes will not come off.

It seems like an excellent design to me from a serviceability standpoint, as you can R&R the core without taking the dash out, and the HVAC case out, as in many other cars, older VAG models included.
 

Red Shed

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You did remove the screw between the two fitting on the firewall correct? Otherwise the tubes will not come off.

It seems like an excellent design to me from a serviceability standpoint, as you can R&R the core without taking the dash out, and the HVAC case out, as in many other cars, older VAG models included.
i dont like that both the heater core inlet and outlet hoses are both at the top of the heater core. i see that they changed this design with the mk6. makes completely flushing it almost impossible. also how the heck to you even get at the heater core hoses going into the firewall without going from underneath. no room with the charge pipe ect in the way. i did see that 6mm allen bolt talked about in the directions for heater core removal but i cant for the life of me get at it. i tried removing the metal clips and wiggling pulling the fitting off to get at the bolt. i also tried various combinations of tools to just try to get at the bolt without removing the fittings. no luck. so now ive got some various fittings attached to a garden hose and am flushing the heater core. i got some white flaky (possibly calcium) deposits out so far but i fear theres alot more in there. i dont see a way of properly flushing it without removing it but i dont see a good way of getting at that bolt. any tips would be helpful.
 

Red Shed

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so a quick trip to the hardware store and i got myself some fittings and hooked up a homemade heater core flushing system. the first couple i put in containers for proper disposal but after that i just went into the sink cause it was just water. i kept switching the direction of the water going in and blowing out with compressed air each time. probably went back and forth about 40 times. till there was almost no sediment coming out anymore. i bet theres still some crap in there but i cant figure out how to get to that bolt. i picked up some new vw coolant and ill hook everything back up and test it tomorrow.
 
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