Anyone Swapped Out A Heat Matrix? Or Other Possible Reasons No Heat?

My 07 A3 has no heat through the vents, though the matrix if I feel the pipes or stick my hand up the passenger footwell can feel the matrix gets as hot too. Yet theres no heat through the vents, if I stick the heat up to HI theres heat for a second then it goes cold, which is weird.

Any garage I ask just say blocked heater matrix, but the matrix itself feels like it gets hot, or could it be getting hot by radiation then being quickly cooled when the climate blows air over it? Ive changed a heater matrix in an older golf and it was a nightmare dash out job, this can only be worse being stuffed with more technology.

I have looked in VCDS and theres a sensor that I think may have an open circuit called outside fresh air temp (iirc) as it reads -50, but would this have any effect on the vents not allowing the hot air? I would have thought it would have the opposite effect.

The air con works fine, very cold actually and there are no errors in VCDS.

I think I really need this fixing before winter comes as I'm not going to be able to defrost the car.

Yes everything is working apart from heat, the flaps can be heard moving and everything, just doesn't blow hot air

Ok it's worthy trying what do I do for this?

It's not that when you turn it up in temp it stops working, the air still blows, it's just still cold

I've flushed and flushed the heater matrix and some globs of gunk came out, it is now better, as in it will get a bit warm as opposed to no hear whatsoever, so I conclude it is the heater matrix blocked and I have partially unblocked probably the top portion of it.


Which means I still need to replace it to get good heat.

Has anyone replaced on of these? I've heard there's a way you don't have to remove the dash to replace it.

I replaced the heater matrix today, the dash doesn't have to come out, just the glove box and centre console to give access to the heater box, then it just slots in, red hot now.

Here

I took a grinder to the old one to see what was going on, one side completely blocked up with all kinds of crap, more previous owner moronic behaviour no doubt