Motorists across the UK are being issued a critical warning that could save them from a hefty garage bill and the frustration of a dead car battery. The advice comes from a seasoned used car expert who has pinpointed a common yet costly mistake drivers make every day.
The One Button You Must Avoid
According to the expert, the culprit is the innocuous-looking front demister button. While essential for clearing windscreens on frosty mornings, using it at the wrong time is a recipe for disaster.
"This is the one button you should never, ever press when the engine is off," the authority states. The reason is simple but devastating: the demister activates the air conditioning compressor to dry the air, placing an immense and immediate drain on the vehicle's battery.
Why It's So Dangerous
Car batteries are designed to provide a powerful burst of energy to start the engine, not to run high-demand electrical systems while stationary. The front demister is one of the most power-intensive features in a modern vehicle.
Pressing it without the engine running can decimate your battery's charge in a matter of minutes. What you might think is a quick 30-second blast to clear the screen could leave you stranded, requiring an expensive jump-start or even a full battery replacement.
How To Correctly Demist Your Windscreen
So, what should you do on a cold morning? The correct procedure is straightforward:
- Start your engine first. Always.
- Then, press the demister button.
- Allow the engine to run while the system clears the glass.
This ensures the alternator is actively replenishing the battery, handling the massive electrical load without any damage being done. It’s a small change in habit that protects your wallet and your vehicle.
Protect Your Pocket
With the cost of living squeezing household budgets, avoiding an unnecessary £100-plus battery replacement is more important than ever. This simple piece of advice is essential knowledge for every driver, whether you're a new motorist or a seasoned road veteran.
Remember: engine on first, demist second. It’s the golden rule for a stress-free winter.
