William O'connell

Hello out there

I have a 2002 A6 2.7t, this thing has been a beast of burden. Currently, having heat issues as in I only get it when driving. The heater core is good, both hoses are hot going to and from. The Tbelt water pump and thermostat and afterrun pump have all been done with in the last year.

The Econ button is on, but when I shut it off I get nothing but cold air coming out of all vents. I'm leaning towards thinking it's the interior ambient temperature sensor, but was also wondering if it could be the CC unit it self that's cooked.

By the way I have researched and read a lot here and other Audi sites with no real clear answer to my particular situation.

Thanks ms in advance

georgeb944

VCDS will diagnose the electronic components of the climate control system.

If you want to easter egg it by throwing parts at it, it could get a lost more expensive. IIRC, the interior ambient sensor is an integral part of the CC unit, and cannot be separately replaced.

uberwgn

Yeah, I'd agree with completing a VCDS scan and try to pickup faults so you have a basis for replacing parts...

meternerd

There's really no reason not to have it in Econ when you need heat. With Econ off, the compressor can run and add cold air to the warm air. The only time the compressor is useful in cold weather is when you need to defrost. I never use my heater without it in Econ. If your air conditioner works in the summer, you may not have a problem at all.

Inablackout

So the internal temp sensor is built into the controller?

I have the heat set to HI, but it doesn't get blow me out of the car heat. If I turn recirculate off it opens the fresh air flap under the cabin filter and sucks in cold air. I would assume running with out the Econ button with the heat set to HI would still make plenty of heat, but all I get is cold air coming out of all vents, even with recirculation on.

Could the external temp sensor be bad and that's why the CC unit is throwing cold air?

I don't have access to VCDS scanner.

meternerd

Mine does the same with it in Auto but not Econ. In econ, it's fairly warm, but definitely not hot. If you're not getting warm enough air, you could have a problem with your heater core or you could have air in the coolant system. You MUST bleed all of the air out of the system or the heat will work poorly or not at all. On cold start with the heater on Econ, the fan is hardly running. As the engine warms up, the fan speed increases until it gets about 1/2 to 2/3 towards full on the display. If yours is doing that, the sensor and controller are not your problem.

clancy

This is a thread form the B5 not C5 so the heater core may be different. However, it is definitely worth reading this, especially post #11 and #14.
https://www.audiworld.com/forums/a4-...2860332/page2/
This is common to have obstructions in the heater core and thus killing the ability to transfer heat to the cabin. The heater hoses will still both be hot to the touch so don't let that fool you into thinking your core is fine. I am not saying yours is not, just that this is worth considering. Your issue may be something else.

Inablackout

Thanks!!

I been considering the possibility of the heater core being a bit clogged. Guess I'll have to vacuum the system and pull the core. Doesn't look to be a difficult task

Inablackout

clancy

Inablackout: Great news about how easy it is to swap out a heater core. Nice video... Please consider cutting open your old heater core so we can see what it looks like. I am curious to see if it is similar to the one in the link that is in a B5 Audi. Does your core have the same issue with clogs or a broken baffle in the end cap?