Some purists complain that the modern-day car is too smart for its own good and that it contains way too many electrical gadgets that have a propensity to go wrong. Whether you agree with this philosophy or not, you may nevertheless be facing an issue linked to your rain-sensing wipers. How can you get to the bottom of this so that you can enjoy uninterrupted passage through that storm?
The rain-sensing wipers fitted to your vehicle are intended to be a safety aid so that you do not need to take your hands away from the steering wheel. When the sensor mechanism detects the presence of water on the outside of the windscreen, it'll automatically send a signal to the ECU which will, in turn, activate the wiper blades.
Usually, this gadget relies on an infrared sensor that will scan the surface of the glass and detect any anomaly. As soon as it does so, it will automatically assume that this is rainwater and that you need to clear the screen.
First Place to Look
Sometimes, the wipers will activate on a perfectly sunny day and may seem to have a mind of their own. In this case, you may have some dirt on the windscreen or, alternatively, the sensor mechanism may be loose. Clean the inside of the windscreen very carefully, and have a look at the sensor box. Designers will typically mount this behind the rearview mirror, and you need to ensure that it is still fixed properly in place. If it works loose it can trigger a false reading.
However, if the system fails to activate at all, then an electrical fault may be to blame. You may need to clean the wiper control switch using a proprietary solution, or you may find that the rain sensor module is playing up. The module may be mounted underneath the bonnet and towards the top of the firewall. If you know where to look and what to do, you can connect a test light to the power source and see if it's receiving energy. If not, then you may have an issue with part of the wiring loom and may be dealing with a short circuit. However, if voltage is present, then you may need to replace the sensor module altogether.
The Easier Path
Typically, it is easier to take the vehicle into an auto electrician. They will be able to pinpoint a problem and repair or replace the relevant components in short order.
Contact an auto electrical service for more information.