Sometimes head units need a reboot or a return-to-factory-settings button to be pressed. Often, there will be a tiny hole somewhere on the face of the head unit. Into this, you insert a thin piece of wire or a toothpick (or similar) and press just hard enough for the screen to go blank and the unit to reboot. It sounds like you’re using the factory Mazda reversing camera with an aftermarket head unit, so you may need to visit a car audio specialist to get it all working together.

Changing a car’s battery can often be enough to scramble the settings on things like cameras and stereos. You may need to find the security code for the head unit to make it all work properly, too.

We have heard some reports of Ranger and BT-50 (they're the same vehicle mechanically) suffering oil pump failures with fairly terminal results for the rest of the engine. The other quirk with this engine is that you can't drain the engine of oil and leave it for any more than a few minutes without the pump running dry and needing to be primed before the engine is started.

Not all mechanics know this and many a Ranger or BT-50 engine has been destroyed when the oil has been dropped from the sump and the mechanic has gone to make a cup of tea or do some paperwork. They return half an hour later, replace the sump plug, fill the engine with oil and start it up. But because the pump hasn't primed, there's effectively no oil pressure and the engine is reduced to scrap in a few short seconds.

The problem is partly to do with the different design of the pump and there are even companies that have engineered more conventional oil pumps to replace the standard units on these engines.

If this is a new phenomenon, then it’s almost certainly down to the condition of your tyres. As tyres wear, they become less able to clear the water between themselves and the road surface, allowing the car to almost 'float' over the bitumen, leading to the loss of traction you’re experiencing. But even a tyre that is simply old (as opposed to worn out) can cause the same problem as the rubber hardens and loses its ability to grip the road. This will also be most noticeable in wet conditions, which is when you’ve experienced it.

Another possibility is that the car has sprung an oil or coolant leak which is spraying from the engine bay, under the car and on to the rear tyres, causing them to slip. But that’s a lot more of a long shot and a close inspection of the tyres would be the first step to curing what is a potentially very dangerous situation.