Troubleshooter: Why can’t automakers make a waterproof car interior?

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Barely an ad goes by that doesn’t show an SUV or pickup splashing through the water, but why can’t we hose down their interiors yet?

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Troubleshooter: Why can’t automakers make a waterproof car interior? Back to video

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We’ve discussed the volume of sensitive electronics that automakers stash inside of their vehicles in several earlier columns. Presumably it’s to protect more vulnerable components from the worst that our driving environment can throw at them. Some rides have main wiring harnesses and connectors running under the floor carpeting, some have main engine computers mounted on the floor with only a metal shield to keep passengers’ feet from crushing them, and others seem to jam computers and modules anywhere they can find the space. None of these designs and build features would be of much concern if vehicle interiors really were a safe, warm, dry space to house electronics.

At it turns out, however, it does in fact rain from time to time, and we fallible humans sometimes forget to roll up windows or close sunroofs. Scarier yet, it is of course entirely normal to track winter snow, slush, and ice into our vehicles where it melts and trickles who-knows-where.

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Many onboard vehicle computers have a constant power supply, even with the engine shut off. If their power-supply connector gets wet enough it can trip a built-in fuse, rendering the unit to the scrap heap, or severely inhibiting the board’s function. If the moisture level is low enough to avoid this scenario, it can still damage the circuit by allowing corrosion to build up on the connectors’ pins. As most of today’s vehicle computers operate on low-voltage signals, it doesn’t take much corrosion to thwart communications.

Placement of these computers or modules can be a major problem. For example, late-model Ram pickup trucks have their keyless-entry and -ignition receiver modules mounted on the inside surface of the cab’s rear wall. Leave a rear slider-glass open in the rain, and you’ll likely end up with a truck that won’t start and in some cases won’t even unlock.

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So how do we keep our precious electronics from turning into useless mush? If you don’t have proper waterproof floor liners (think WeatherTech and similar products), get them. They’ll go a long way to help keep the floor carpeting dry, not to mention preventing salt stains. Those thin vinyl or rubber floor mats your retailer may have thrown in with the vehicle reduce abrasive wear, but are absolutely useless for keeping water off the carpeting.

If you’ve left a window open and the worst happens, grab a wet/dry shop vac and remove the filter. Start vacuuming up as much moisture as you can with the wet-rated shop vacuum cleaner and use some absorbent towels to get as much surface wetness dried up. Check the under-padding by lifting up a section of the carpet’s edge by a door (you may have to remove a scuff panel). If it’s soaked, you’ll have to get it propped up off the floor with a brick or wooden block and then get a fan or heater aimed at it from the outside for a few hours or longer to dry things out.

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If you notice a water leak from a defective windshield or door seal, don’t ignore it. Water leaks that drip behind the instrument panel can cause the most damage, as this area is home to the majority of the vehicle’s wiring and a bulk of its computers. If your ride has a sunroof, check its drains in spring and fall. This task is as easy as opening the roof and then pouring a glass of water in the trough that runs around the perimeter of the opening. If the drains are clear and free, you should see water running out just behind the front wheels and just ahead of the rears. If not, you can try the dishwashing-liquid hack by pouring some of it directly into the corners of the trough followed by a small amount of water. Keep a shop vacuum at hand in case the trough fails to drain.

Finally, if any carmakers are listening, here’s my $10 idea. For all those well-equipped vehicles with rain-sensing automatic wipers, how much trouble would it be to include some software that would close any open windows or sunroofs if the windshield sensors detected rain while the vehicle was parked?