Hyundai IX35 Pricing and Specs

A poor earth is often the cause of this sort of misbehaviour and it’s a good place to start looking. Check the earthing points in the engine bay and around the area where the tail-lights are earthed in the cargo area.

You might need to lift some carpet or trim pieces, but when you find the earth points, make sure they’re tight and clean and not covered in corrosion. Don’t forget to check the tightness and cleanliness of the battery terminals, too.

Beyond that, these symptoms point to a problem with the car’s body computer which controls all these functions and many more.

When this computer starts to die, all sorts of weird and random flaws can occur. But try this first: Disconnect the battery of the car and let it sit overnight. Reconnect it next morning and keep a close eye on what happens. Sometimes this simple trick will reboot the body computer and normal service will be resumed. Best of all it’s free.

I’m not sure that this is a common fault, but it’s certainly not unheard of. The stereo in a modern car is like any other electrical appliance; it has the potential to just up and die for no good reason.

But rather than simply replace the unit you have, why not shop around for an improvement. There are many, many, aftermarket stereo systems that will fit your car and will have superior Bluetooth functionality and more features than the stock head unit from 2015. You might find they’re cheaper, too.

When a bunch of electrical functions all go out at once (or within a short space of time of each other) suspicions are always drawn to the car’s body computer. This computer controls all the functions you mentioned as well as dozens of others from the heating and cooling, central locking, lights, wipers, dashboard and much, much more. When the computer starts to die (as most computers eventually do) these functions will start dropping one by one and sometimes in simultaneous batches of failures. Eventually, pretty much nothing will work and the car will not even respond to the key’s inputs.

An auto electrician is the best place to take the car, and as well as the computer, they will also check the car’s battery and charging system and the quality (or otherwise) of the car’s earthing points. Bad earths can cause similar problems to this, but the body computer remains a likely culprit.