I've just carried out a Climate Control Evaporator change (not fun). I also swapped the heater matrix 'cos it was furred up with corrosion residue and probably due to start leaking big time.
I won't say it was a piece of cake 'cos even with the step by step guide from another American site it damn well wasn't. I'll certainly never do one again, and I've been swapping dashboards and interiors for years on other cars.

Apart from many other hidden pleasures, you need special 'unlock' tools to remove the aircon pipes from where they fit into the evaporator on the bulkhead just under the upper engine mount. These tools resemble a tubular plastic 'clamp' which hooks around each pipe (different sizes for each pipe), then by pulling on the clamp it forces a 'ring' (apparently called a 'cage' - basically a coiled spring which runs around the pipe in a collar) into the pipe and this releases the pipe from the evaporator and allows it to be removed.

So far so good, but five days down the line (due to things breaking and the Volvo Dealer not supplying the correct 'O' rings etc), when re-assembling, I push the pipes (suitably bedecked with new 'O' rings and lubed with the correct PAG oil - don't ask, it's a nightmare) back into the evaporator but I can't find a way of getting the 'cages' to release again, meaning that I can easily pull the pipes back out again. I expected them to 'latch' into place as happens with the heater hoses, but so far, no joy. Any techies got any ideas?