The fan only blows cold air. I have replaced the hedgehog (FSR) as it did not blow at all at one point. I have also replaced the water heater valve, twice with used parts and not sure if they are working properly or if it is another problem. Before I changed the valve it would get the tiniest bit of warmth come through eventually but only on one side of the car, now 2 valves later and I get nothing at all. Any ideas? The temperature gauge moves nicely up to the middle and stays there...

Stick with new parts mate it always doubles the cost, i would suggest getting a diagnosis from an independent first.

i am not too familiar with these but is the actual matrix getting hot at all.

Stuck thermostat?

Just throwing in ideas.