Is it okay to have a larger inner diameter vacuum line for a car HVAC switch?

Yes...it's OK to install a larger diameter hose or line in place of a smaller one for vacuum applications/situations. In fact, that is a typical repair process if the vacuum line is hard plastic with a formed rubber end that fits onto a vacuum T fitting or device. If the rubber end is degraded, loose or broken, just cut it off making sure not to crimp the plastic line closed and install a larger diameter vacuum hose onto the hard plastic one that will fit snugly and allows the rubber hose to slide onto the port or nipple. Lubricate the hose end or fitting/nipple with some water or saliva if needed to slide on easier. Parts stores usually sell graduated or stepped plastic fittings or adapters that also allow you to go to bigger or smaller vacuum hoses as needed when making splices.

does it work? If it works and doesn't look to rude that it upsets you its ok its surely its not making the car dangerous

Hi so it will not make them work quicker if anything slower.

okay