Freezing Cold A/C (only) in 2005 Passat TDI GLS

fastcar4re

Veteran Member
Joined
Sep 3, 2008
Location
Houston, Texas
TDI
2015 Jetta TDI SEL (purchased as "new" in May 2017).
My A/C is now blowing maximum freezing cold, and will not adjust warmer at all. In fact, the heat is not working at all either (which explains the maximum cold). In May of 2015 I had the heater core replaced by VW because of the same issue. I also had the coolant replaced. Could the same problem happen again in 2 years and 20,000 miles? The first heater core lasted about 10 years.

When I turn the temperature knob, the same resistance is still in the knob, and I can hear the airflow change and the volume (slightly), but no warm air.

Has anyone put in a 2nd heater core?

Any other thoughts?
Thanks.
 

vwztips

Veteran Member
Joined
Aug 30, 2009
Location
Greenville, SC
TDI
2005 Passat GLS Wagon TDI 5 spd manual w/BSM delete 2011 Tiguan TDI/DSG 2005 Audi A4 Avant 6MQ TDI 2011 BMW X5 35d
Have you confirmed the heater door is actually closing and opening fully?
 

imo000

Top Post Dawg
Joined
Dec 13, 2005
Location
Cambridge
TDI
2009 M-B ML320 Diesel & '05 Passat TDI Manual 5-Speed
Do you have enough coolant in the engine?
 

whizznbyu

Veteran Member
Joined
Jul 11, 2006
Location
Waxhaw, NC
TDI
2015 Golf Sportwagen 6 speed manual. B5 died at 302k miles.
Isn't the heater core inside the guts of the dashboard? I understand it takes a whole day to get it out and put it back in, if you're good.
VW dealership didn't know what else to do after they suggested that swap?
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
If you feel the heater hoses, are both warm?

Have any little bit of foam been blowing out of the air vents?

-J
 

imo000

Top Post Dawg
Joined
Dec 13, 2005
Location
Cambridge
TDI
2009 M-B ML320 Diesel & '05 Passat TDI Manual 5-Speed
Isn't the heater core inside the guts of the dashboard? I understand it takes a whole day to get it out and put it back in, if you're good.
VW dealership didn't know what else to do after they suggested that swap?
Go to another dealer or a shop that know what they are doing.
 

Smokerr

Veteran Member
Joined
Sep 3, 2005
Location
Alaska
TDI
Passat Wagon GL,2005,Silver
Ok, this is too weird.

Your cold has nothing to do with heat. The cold is simply more or less compressor clutch engaging.

Turn it to HEAT and see if the heater puts out.

It sounds like your relay is welded across and won't let the clutch do its job.

Maybe the dial is not working?

If the AC button is OFF and you are getting cold, then the compressor is running full time

Why would you want anything but max AC there anyway. 120 degree?
 

fastcar4re

Veteran Member
Joined
Sep 3, 2008
Location
Houston, Texas
TDI
2015 Jetta TDI SEL (purchased as "new" in May 2017).
Thanks for the comments. I have not had time to look at it yet, but I'll check the linkage behind and to the side of the glove box. I suspect something plastic broke due to fatigue (e.g. door part). Yes, swapping out the heater core did take an entire day, and it worked great for 2 years after that. The loss of heat was abrupt this time (gradual last time), so I suspect it is not a plugged heater core again so soon. I replaced with new coolant, when I had it replaced the last time, so dirty coolant should not be the issue. The engine has plenty of clean coolant at this time. The AC and heat are totally separate on this vehicle in that to warm the cool AC air coming out of the vents, warm air is blended in as one turns the manual knob increasingly to the red and out of the blue zone. I have not had bits of anything flying out of my vents, which still blow relatively strong on all settings. The heater does not put out at all. There is obviously an issue with the heat side of the situation.
 

Smokerr

Veteran Member
Joined
Sep 3, 2005
Location
Alaska
TDI
Passat Wagon GL,2005,Silver
Seldom anything as coincidence

There should be a common link between the two.

Possible that there is an interlock that does not allow heat and cooling, will test that.
 
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