This is definitely not the sort of information car makers publish. Instinct suggests the headliner should, indeed, fit through one of the door openings, as that’s how it would be fitted on the production line. Try a front door opening first with the front seat slid all the way back and the backrest laid right down.

The other option would be to politely ask a motor trimmer how they manage this job.

A typical air-conditioning system in a car uses an engine-driven pump (compressor), heat exchangers and lots of ducting as well as a decent volume of compressed refrigerant gas to make it all work. If any of these things is out of kilter, the air-con may stop working.

Low gas levels, a worn out compressor, compressor clutch, or an electrical problem could be the cause here. The system is also full of interlocks to ensure that it can’t be damaged, for instance, by operating with insufficient gas or if the temperature of the system becomes too hot. At the other extreme, you might simply have a blown fuse that controls the fan circuit, at which point the system will not work either.

The best solution is to take the car to an air-conditioning specialist. The first thing they’ll do is test to see whether the system is holding pressure. If it is, the fix may be a simple re-gas of the system, at which point, chilled air may be miraculously restored. But you may find you need to replace some parts as well. But a pressure test will often be the first thing tried as the typical car air-con system loses gas over time, and that’s just a fact of life. Eventually, it may get so low the system can’t operate and there’s no more cold air.

This is why it’s important to run the air-con (even in winter) for a minute or so every week. This will help keep the seals lubricated and prevent loss of gas in the long term.

You have a couple choices here. You can either go to a brake specialist or a general spare parts store, both of whom should have what you need, or will be able to order it for you. If it’s not on the shelf, metropolitan stores can generally have the parts for you the next business day. If you can wait a little longer, there are plenty of online sites that also sell the repair kits you need. Some of these sites might allow for local pick-up, but the majority of orders will be mailed to you.

Just make sure if you go down the latter route to use a secure payment system that will refund your money if the parts never turn up. Also, local (Australian) online stores will likely have a faster turnaround than overseas sellers, regardless of any price difference. If you do shop overseas, you’ll also need to decide whether you want the faster (more expensive) shipping option sometimes offered.