Is it really necessary to mess with the AC side to swap a headlight on a 2025 Q5?

You do not need to open the refrigerant circuit. When dealing with these modern setups, the lines usually sit close enough that you can unbolt the adjacent mounting hardware and snake the necessary components out of the way. The lines themselves are designed to be disconnected by loosening their mounting clamps, which avoids the need for a professional recovery station and keeps you out of the shop for a small bulb. Just be careful when unbolting things around the condenser area because those lines are high pressure and should not be handled improperly.

Regarding the bumper, it is definitely more complicated than just yanking plastic. These Q5s use a complex array of interlocking clips and fasteners, many of which are hidden under the rubber trim or behind the wheel wells. You will want to look for specific twist points along the edges before you start pulling hard, or the plastic will crack, and you'll be looking at a much bigger repair bill later.

There is a specific sequence to those clips that usually involves releasing the inner fender liner first. Once that liner is loose, the major bolt locations become visible and manageable. Trying to peel the bumper off starting from the center bolts tends to catch the plastic and tear it, so follow the clip release pattern. It sounds like a pain, but since you've got hands-on experience, you're probably more comfortable with the process than the official manual suggests. Just take your time and use a trim removal tool for those hidden clips to avoid scratching the bodywork.

Agreed on the fender liner being the key step, that was the turning point when I did my buddy's Q7 last winter. The push clips along the liner were so brittle in the cold that two of them snapped just from finger pressure, so I let the car sit in the sun for an hour before touching anything. Once that liner was loose the whole bumper shifted easier than I expected. Keep a handful of spare clips on hand before you start, they're a few bucks and save a trip mid-job.

Gotta push back on the idea that you'd loosen the line clamps at the condenser to get them out of the way. On my Golf I did a similar front-end job and never touched the lines at all, they just flexed enough with everthing unbolted to give me the clearance. Cracking those fittings loose with no recovery setup is how you dump refrigerant all over your driveway, so the whole point is leaving them alone. If the manual says you can get the lamp out without opening the circuit, belive it. Also curious if anyone knows wether the LED module is a seprate part from the housing, since that changes the cost math a lot.

Update: took the tip about warming the car up first and it saved me, the wheel well clips came out in one piece with the liner dropped. Still stuck on the bumper cover though, there's a fastener low near the fog light area that I can't tell if it's a bolt or a clip. Anyone remember how many fasteners run along the bottom edge before you can pull the cover?