Despite the complex electronics of today’s cars, many glitches can still be solved by a simple test lamp.

While most DIY mechanics will shy away from tackling problems involving sensors and the like, many will take on a dodgy light, or kit such as heaters, wipers or switches. And for a quick, easy way of tracking down these faults or a blown fuse, look no further than a test lamp.

Basic circuit testers are little more than a screwdriver with a lead and bulb in the handle, and are often considered to be a poor man’s multimeter, but recent units are more advanced in their design.

Many can show the voltage and polarity at the probe point – much more useful than just knowing whether a feed is live or not.