While not a common problem, this could be caused by a faulty oil pressure sensor. But it’s important to have this checked out by a mechanic because you could be dealing with an engine that really is suffering from low oil pressure. If the latter is the case, you risk doing permanent and catastrophic damage to the engine because the oil pressure is insufficient to fully protect the internal parts of the engine.

The reason you’re seeing the light come on when the engine is idling (and presumably at operating temperature) is because this is when the engine’s oil pressure is at its lowest. When you rev the engine, the oil pump turns faster, creating more oil pressure. When the engine speed drops again, the pump slows, the oil pressure falls and the warning light switches on.

By having the actual oil pressure checked at a workshop with an independent gauge (separate to the one in the car) you’ll know if the light is coming on because of a duff sensor or because the oil pressure really is too low.

The shifter in your Kia is designed to be used in the normal (PRND) range in most cases. If you decide you’d like to control the gear selection yourself, you can flick the lever across to the other plane (+ /-) also called Sports mode, and control when the transmission changes gear. By pushing the lever forward in that second plane, you can force the transmission to change up a gear. Pull the selector back and it will shift down a gear. Hence the + and – symbols.

In most cases, the transmission will stay in the gear you select in Sports mode, unless you try to take off from rest in a high gear (when it will shift down for you) or you’ve taken the engine to its maximum speed, at which point the car will automatically shift up a gear to prevent the engine from blowing up.

The idea of this is that you can drive the car in a sportier fashion (makes little sense in a Kia Carnival, I know). But it can also be handy if you are, say, towing a trailer and need a little more engine braking, at which point you can flick across to Sports mode and force the transmission into a lower gear.

Many owners never experiment with Sports mode and it remains a mystery to a lot of people.

I reckon an early Kia Carnival would make a great platform for a vanlife adventure. It's very unlikely there's a lot of wiring inside the door, and the only electrical wiring that leaps to mind might be a courtesy light for when you open the sliding door, and the little switch that controls it. So, try to find that switch (it's probably down low near the floor) and see if you can see where any wiring enters or leaves the door via the door jamb. Don't expect to see actual wires, as they probably run inside a black rubber boot or sheath to protect them.

Again, it's very unlikely that there's wiring high up in the door near the window (which is where you need to curtain) but if you drill carefully and check the hole for any coloured wiring just as you punch through the metal, you should be fine. A strong torch will help with this, and disconnect the car's battery before drilling just in case you get mighty unlucky.