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I have an '04 A8 D3. It came with heated/ventilated front seats, but the upholstery was bad and one of the controllers failed, so I bought a pair of heated, but not ventilated seats in good shape from an '08 D3.
When I hooked up the heater connector, the heaters came on and stayed on, not responding to the dash control...
My independent mechanic looked at them, initially told me they just needed reprogramming, but then he tried and now tells me that the heated, non-ventilated seats are not compatible with my car because it came with ventilated seats.
Is this true? or do I just need to do some reprogramming with VAGCOM?
I don't see any coding changes required at a quick glance.
It might be the module and it's wiring that you have is not compatible.
Post up a complete unmolested Auto-Scan please.
The temperature sensor may be wired differently...
you need to find out the wiring, I believe there will be a wire that senses the fan on and shutdown the heated function, you need to disable the fan on line somehow for the system to sense that the fan is not on, either a load (resistor). Look at the old seat, measure the impedance between pins in the connector and simulate the same with the new seat connector.
The seat hardware is independent of VCDS. There is no option for Ventilated seat, I went through mine when I retrofit the can bus and the head unit.
Thank you both for your replies. I will follow your leads. However, as the heater remains constantly on, I am not sure about the system now thinking erroneously that the ventilator fan is on. LTOOZ suggestion would imply that the heaters should stay constanly off, not responding to the dash controls.
As it turns out the ventilated seats have a separate module 4EO 959 772, for heater/ventilation control. Despite using identical connectors for the harness from the car, the heater control wires in the seats are assigned differently depending on whether ventilation is present or not. It seems odd to me that Audi would change pin assignments, and not just add the ventilator control wires on unused pins, but it must make sense to them...
I might also just remove the back rest and seat cushion from the new seats and install them onto the old seat base.
Wiring for ventilated and not ventilated seats are different even on the same year cars. You need wiring diagram (Bentley Manual) in order to fix this. That looks easier and less risky than swapping upholstery.
LTOOZ suggestion would imply that the heaters should stay constanly off, not responding to the dash controls.
Since the new seats don't have ventilated fan options, you must make the system thinks that the ventilated seats are "OFF", not the heated function. You need to find out which pins are for temperature sensor and heat elements and connect them accordingly. All the heated seat dials are correspond to a temperature = temperature sensor. If the temperature sensor is wrong, then the heated function will be wrong. Now, the heated function is always on, which means it's working, it just doesn't respond to the dial because the temperature sensor is NOT connected somehow. At least that's how I interpret the problem. I haven't seen the plug, since I never had to, but I'm sure they're bundled with the power seats and memory also?
Even with the wiring diagram, it's still hard to read and figure out.
Please take the pictures and post how you remove the skin...
Originally Posted by tarthol
I might also just remove the back rest and seat cushion from the new seats and install them onto the old seat base.
That would be very helpful for many who want to do the same thing. The only problem is the new skin doesn't have perforated part for the ventilated function. You should just sell the set and wait to get a new set with ventilated seats.
LTOOZ: thank you for explaining further. I understand what you are saying now, and that makes perfect sense.
In, fact, removing the seatback and the lower seat cushion are very simple. Since it doesn't require 1) getting the wiring diagram, 2) interpreting the diagram and 3) altering wiring, I think it is the best option. The original wiring is maintained and no worry that a jury-rigged attempt to fool the system will fail, leaving the heated seats back on, full blast.
The ventilation option never seemed to do much anyway. And the perforated leather is terribly vulnerable to tearing along the perforations. I prefer the smooth leather as well.
To cap this off, I removed the seatbacks and the lower seat cushions from the unventilated '08 seats and put them on the ventilated '04 seat bases. Now the heaters works properly.
Removal of the seat backs is simple. Just follow the steps in this PDF:
Removing the lower seat cushions is straightforward as well, but takes a little effort to unclip the retainer wires from the five white clips on each side.
Dismantled seat.
Side and front trim, trim bracket and bracket plates.
12-12-2014, 02:09 PM
D3 front seats replaced, heater problem
