Re: 155 heater matrix
Not done the whole Matrix but i did do the Heater Tap. Fixing the tap itself was straight forward, it was gaining access to it that was the problem, I ended up having to rempve the entire dashboard right up to the Left side of the steering wheel!! not an easy job.
I seem to remember someone in the past saying it is possible to do the tap without all this but not sure how, certainly if the matrix is to be replaced then yes it will all have to come out.
Hope this helps.