That’s a crazy set of circumstances, but it wouldn’t be the first time an apparently unrelated component has thrown another into disarray. On the surface, there’s no way the climate control or headlights could affect the way a transmission works, but here we are…

The most likely explanation is that the electrical gear that’s locking the transmission into third gear is somehow affecting the transmission’s speed sensor that tells the computer the vehicle is travelling fast enough to select fourth (top) gear. The body computer could be the culprit, but there could also be a problem with the car’s wiring loom that is creating this havoc. A poor earth could also be causing the problem and is a more common cause of transmission problems than many people imagine.

It sounds like a pretty nitty-gritty tech question, but is the camshaft in the engine of the Kia Rio timing belt or chain driven? There’s a good reason for knowing the answer, though, as it determines whether you need to add a crucial routine maintenance step to your ownership.

In cars with a toothed rubber timing belt, the belt and its tensioners need to be changed at an interval recommended by the car’s manufacturer to avoid expensive belt failures which can ruin the whole engine. Ignore this maintenance at your peril.

The good news is the GL4C engine as used in the Kia Rio since 2016 uses a timing chain which should be good for the life of the engine and not need any extra maintenance.

Yes, there are plenty of companies selling replacement keys for this car. The cost will depend on whether it’s a conventional key or an electronically coded key with a remote locking function built in to it. Just be careful if ordering online, though, as some replacement keys include only the hardware and not the internal electronics.

In many cases, you need to source the replacement key and then have a locksmith physically cut the key so that it works in your car. In some cases, you may have to prove ownership of the car before the locksmith will do this. Some keys then need to be electronically coded to `talk’ to the vehicle.

If you want a no hassle experience, there are even locksmiths who will come to you and cut the key on site, but you’ll pay a call-out fee as well as the cost of the key itself.