The moral of the story is, if your vehicle has a water leak, fix it. No need to read any further?
In case you did not know, every year vehicles become more electrical devices than mechanical devices, much to the chagrin of us mechanical types. A few years back I had a dream that I would build a fuel control system (carburetor) that was completely mechanical and would compete with the latest direct injection fuel systems. Not gonna happen. I am spending too much time trying to learn electronics. Likely excuse.
Back to the water leaks. Water is the enemy of electrical systems, especially when mixed with a little salt. As you may know salty water is a fairly good conductor of electricity. When salty water gets into the many electric/electronic components in your car the results can be a real challenge to the most astute automotive mechanic.
When a vehicle is brought in for a diagnosis not many customers mention the puddle that appears on the floor everytime it rains. Instead they say “every once in a while my starter refuses to turn over my engine”.
During my quarter century of repairing cars as a professional there is one very important fact I have learned. Water leaks are driven more by gravity than any other force. Any holes in your vehicles floorboards are likely letting more water out then in.
The worst and most common water leak into your car is around the windshield. Windshield leaks usually funnel water under your car’s dashboard. Unlike under the hood where electronic components are designed to get hot or get wet and still function (NOT PRESSURE WASHER WET) under the dash electrical components are where your automaker saved some cash. By design the dashboard is a haven of electronics. Relay panels, fuse panels and modules of every kind are squeezed into every last square centimetre of space. These components are not at all designed to get wet. When they do their behavior will be way less than consistent.
Copper is still the electrical conductor of choice and many times your mechanic will find some green electrical connections that are the reason for your vehicle’s maladies. A couple of connections or a relay may be all that is needed to make a repair. On the other hand when your engine control module fills with water it will cost quite a few more dollars to get back up and motoring again.
Now that your car works again, do not plan on driving it again out of doors until the water leak is fixed. You have to fix that leaking windshield.
You can bet when your vehicle was made the manufacturer went to a lot of effort to make sure the windshield did not leak. Today’s windshields are typically glued in place. They were glued under perfect conditions. Windshield replacement is very common in our part of the country. Not many of us make it too many years without getting one replaced.
When it comes time to get your windshield replaced be sure to use a professional installer. The care and preparation of the sealing surface is very important. As well, the windshield is a structural part of your vehicle and the glue must be allowed time to cure to reach both its ultimate strength and seal.