back to article Sniff the love: Subaru's SUVs overwhelmed by scent of hair shampoo, recalls 2.2 million cars

Japanese automaker Subaru has told the US National Highway Transportation Safety Administration that it plans to recall some 1.3 million vehicles in the US because of emissions problems. It plans to do the same elsewhere in North America and in Japan, bringing the recall total to around 2.2 million. The issue isn't vehicle …

  1. Kevin McMurtrie Silver badge

    Automotive switches are normally sealed or self cleaning because of oxidized oils, brake dust, road dust, pollen, silt, soot, dead skin, fabric fibers, hair, etc. People make a mess of their car using cheap silicone leather and dashboard cleaner but that shouldn't ruin important switches.

    1. Paul Crawford Silver badge

      I suspect there might be a more serious reason than brake lights not coming on - maybe this is also the means to disengage the cruise control?

      As other commentards have already mentioned, most likely it is a "new" designer that lacks the knowledge that most switches are not suitable for near-zero current and so you need to have some significant current (by microprocessor interface standards, only a few mA in most cases) to make it work reliably. You get (or used to) more expensive switches with gold flashing for "dry" switching, but then they are not suited to high currents as it blows away the few um of gold.

      1. Stevie

        Zero current etc

        Eee, it meks yer wunder 'ow we managed when t'cars were full o' inexpensive mechanical switches, dunnit?

    2. ckm5

      That's simply not true, switches inside cars are almost never sealed. I have been working on cars for 30+ years and I don't think I've ever seen a car with fully sealed switches.

      As far as 'self-cleaning', that sounds like a bunch of marketing hype. Yeah, terminals probably scrap of the gunk, but that's hardly a design feature.

  2. Gene Cash Silver badge

    Those must be some seriously cheap & shitty switches. I think Radio Shack stuff was better than that.

    1. Steve 114


      A nice little arc used to clean contacts. Could it be that LEDs don't draw enough current?

      1. Down not across

        Re: Progress?

        Could it be that LEDs don't draw enough current?

        Not only that. You got things like BMW's LCM (as an example) where all lighting is controlled via a module rather than direct from switch so current draw on many switches is unlikely to be that high these days even without external lighting changing to LEDs.

        1. Adrian 4

          Re: Progress?

          Aren't brake lights usually controlled by brake line pressure these days ?

          1. fredds

            Re: Progress?

            As far as I know they are still controlled by a switch, activated by movement of the brake pedal. Operates quicker, and doesn't rely on having pressure in the system, or keeping high pressure fluid out of the switch.

            1. BebopWeBop

              Re: Progress?

              Well on mine, it certainly is not sustained pressure on the brake. One way to get some arsehole tailgater to back off is to very lightly touch the brake and without having a physical effect, the brake lights come on giving said tailgater a bit of a shock.

              1. Anonymous Coward
                Anonymous Coward

                Re: Progress?

                I'm just waiting for the day when there's an idiot tailgater a metre or two behind me and something comes out in front of me. (Or a leaf blows across, or a dog/pedestrian, etc.)

                They're going to be part of the rear end of my car before I even realise the Autonomous Emergency Braking has activated...

                1. Anonymous Coward
                  Anonymous Coward

                  Re: Progress?

                  Personally I'd try and avoid that as much as possible. Whilst driving on someone's tail is clearly stupid and your emergency stop will almost certainly damage their car it's also quite likely that you'll get whiplash and have the hassle of sorting out insurance etc...

          2. Orv Silver badge

            Re: Progress?

            Pressure-operated brake light switches were a common thing on older vehicles -- usually sharing the same switches used to trigger the brake warning light if pressure was lost in one circuit. They're not favored anymore because they cause more of a lag in turning on the brake lights, and it's often possible to brake lightly without triggering a pressure-activated switch.

        2. Fungus Bob

          Re: Progress?

          Not just BMW. Chrysler products have used a Body Control Module to control every switch, light and gauge not directly running the engine or transmission for years. Fuel level, brake lights, headlights, door locks, windshield wipers...

          I suspect most carmakers do things this new and stupid way.

          1. John Jennings

            Re: Progress?

            Every major car maker uses modules these days. it reduces weight in wiring and switchgear.

  3. Pascal Monett Silver badge

    Holy cow, it's everywhere

    So now I learn that we emit potentially noxious gases simply by wanting to stay clean and smell nice. Terrific. What other doomsday mechanism will our consumer society dump on our ignorant hides ?

    It might be time to slow things down a bit and not rush to production with every half-baked idea simply because we can.

    1. Mike 125

      Re: Holy cow, it's everywhere

      The Precautionary Principle isn't popular in our neo-liberal culture. Our overlords tell us we must all have the freedom to consume, pollute and degrade. It's our human right. Actually, our it's our duty, they say.

      Meanwhile: Ooooh, glyphosate’s on special offer at B&Q, quick let’s get down there in the Subaru.

    2. Andy Non Silver badge

      Re: Holy cow, it's everywhere

      "simply by wanting to stay clean and smell nice."

      If humans still exist in a hundred years, society will look back in horror at some of the stuff we put on/in our bodies. Like we look back to Victorian times in horror at people bathing in radioactive radon baths or women putting white lead based cosmetics on their face to have a paler skin or sprinkling talcum powder on your body laced with asbestos dust. Lovely.

      1. Jeffrey Nonken

        Re: Holy cow, it's everywhere

        Personally, I find most perfumes and artificial scents obnoxious, if not downright noxious. One man's "smell nice" is another man's anaphylaxis.

        And before anybody gets snide: I shower daily with tea tree oil soap and Aussie brand shampoo, and change to clean cotton underwear (washed in unscented detergent). I don't get complaints.

        1. Semtex451
          Paris Hilton

          Tea Tree Oil

          Along with beer, Tea tree oil will give you moobs (oestogenic)

          Icon - coz I now have cleavage :(

        2. EuKiwi

          Re: Holy cow, it's everywhere

          Aussie brand shampoos etc. are some of the most obnoxiously over-scented products on the market IMO.

  4. Anonymous Coward
    Anonymous Coward

    This is what happens when you implement diversity and equality...

    Women wearing every lotion, perfume and powder under the sun building cars. No wonder they get contaminated. I expect there's reams of long girly hair everywhere too. And those damn hair grip things.

    It isn't right, I tell you. Let's hope this nonsense stops after Brexit. And don't get me started on that Davina McCall.

    1. Yet Another Anonymous coward Silver badge

      Re: This is what happens when you implement diversity and equality...

      We're you able to get started on Davina McCall? Purient minds need to know

    2. MrDamage Silver badge

      Re: This is what happens when you implement diversity and equality...

      It seems at least 8 people were unable to correctly understand your context as you didn't put a "/s" at the end of it.

    3. Graham Butler

      Re: This is what happens when you implement diversity and equality...

      >And those damn hair grip things.

      I've lived in my current flat for 7 years. Alone. I still find at least one bobby pin every couple of months from the previous owner.

      1. vtcodger Silver badge

        Re: This is what happens when you implement diversity and equality...

        I still find at least one bobby pin every couple of months from the previous owner.

        Bobby pins are thought to be a stage in the complex life cycle of an obscure and poorly studied organism. They seem to appear spontaneously, but actually are the spawn of wire coathangers that have been stored near a phone that is exposed to repeated robocalls. Left alone in the dark, they will eventually morph into single socks that do not match any other stocking you own or have ever owned,

        1. Marcelo Rodrigues

          Re: This is what happens when you implement diversity and equality...

          Douglas Adams would be proud of You! :D

        2. Anonymous Coward
          Anonymous Coward

          Re: This is what happens when you implement diversity and equality...

          So I'm not losing socks after all.

          It's the coat-hangers.

          1. Will Godfrey Silver badge

            Re: This is what happens when you implement diversity and equality...

            It's always the coat hangers.

  5. mark l 2 Silver badge

    Since break light switches have been around for decades without this problem, it appears that Subaru have tried to save a few dollars per car by using a cheap component and it has come to back to bit them in the arse.

    1. Anonymous Coward
      Anonymous Coward

      Not necessarily

      If you read switch specifications very carefully - as you do when designing any electromechanical product - you will know that DC switches have a minimum as well as a maximum current. Below the minimum current, there may not be enough cleaning action from the current itself to keep the contacts working.

      I wonder if this issue is due to the switch being designed in the days when the brake (note spelling) light switches drew the entire lamp current, and now all that goes through is the small current needed for whatever the logic input is to something on the CANBUS.

      Sealing switches is not always a good idea because any arcing can cause deterioration of the insulators, which then deposits crap on the contacts. For logic interfacing, sealed reed units are best because they are glass/metal only. But they are very limited in current and can't be used for direct lamp switching.

      1. David Pearce

        Re: Not necessarily

        Unfortunately they don't teach the need for a wetting current at university these days. Most cars use some sort of micro switch with plunger for this sort of application

        A quick sample from Omron shows something like 1mA at 5V as a minimum ie 4k7, a surprisingly low value for the average fresh engineer.

        1. Will Godfrey Silver badge

          Re: Not necessarily

          For very low current switches, a proper 'wiping' action is necessary to remove accumulated crap - something which almost all reed switches do. Sealed, and actuated only by the proximity of a magnet, they are also immune to contamination.

      2. TonyWilk

        Re: Not necessarily

        My company was caught out years ago by silicone contamination of low voltage low current connectors, grease was used to exclude moisture but in a few months micro fibres of silicon/silicon carbide? grew and insulated the contacts. Cleaning the stuff off and replacing all the connectors was entertaining!

        Safe levels of silicone contamination for electrical contact:



        1. Alan Brown Silver badge

          Re: Not necessarily

          "My company was caught out years ago by silicone contamination of low voltage low current connectors,"

          This is the primary reason I tell people NOT to use silicon grease in electrical connectors.

    2. Francis Boyle Silver badge

      "it appears that Subaru have tried to save a few dollars per car by using a cheap component"

      Or a theoretically better component. The theories bruited above remind me of the problem of LED traffic lights not producing enough heat to melt snow. It can be seriously non-obvious that the effective working of a system relies on some unintended and unnoticed side effect of the operation of a single component.

      1. imanidiot Silver badge

        The theories bruited above remind me of the problem of LED traffic lights not producing enough heat to melt snow.

        Not really a problem most of the time. And easily solved by including a small heater that is only switched on at sub zero temperatures (This is still more power effective than incandescent bulbs). Alternatively I've heard that even just applying a non-stick coating to the lenses is enough. It's just that for the early models nobody ever thought it could be a thing.

    3. ckm5

      As someone else pointed out, they probably switched from gold plated to unplated switches as they were $0.00001 cents cheaper.

      1. david 12 Silver badge

        "Low voltage and low current"

        They probably switched to LED brake lights: the low voltage isn't enough to reliably make the contact.

  6. Phil O'Sophical Silver badge

    pedal area

    The issue would more likely be linked to cleaning products used around the brake pedals

    Or shoe cleaning and polishing products?

    1. fidodogbreath

      Re: pedal area

      The issue would more likely be linked to cleaning products used around the brake pedals

      Which begs the question: who thinks it's a good idea to use slippery silicon-based cleaners on a brake pedal?

      1. M.V. Lipvig Silver badge

        Re: pedal area

        "Which begs the question: who thinks it's a good idea to use slippery silicon-based cleaners on a brake pedal?"

        Every used car dealer in the world, and detailing shops jump to mind.

      2. Kubla Cant

        Re: pedal area

        who thinks it's a good idea to use slippery silicon-based cleaners on a brake pedal?

        Most hand car washers spray noxious air freshener in the footwell.

      3. jtaylor

        Re: pedal area

        My clutch pedal started squeaking and groaning. I cured that with a few shots of silicone grease where the pedal arm rotates against the bracket. (Silicone grease won't destroy the hydraulic seal that's exposed a few inches behind this.)

        I'm not the first person to do this.

        I really hope I didn't create electrical problems under the dashboard.

  7. Stuart Halliday

    So that'll apply as well to switches in domestic goods, laptops and desktop computers.

    Hmmm interesting...

  8. Anonymous Coward
    Anonymous Coward

    smells like

    Environmental factors like the shampoo the car's driver uses or the brand of hand lotion used by the tech building the car seem far fetched. A much higher possibility is the use of an adhesive that contains silicone on a part in close proximity to the failing switch. That would give 24x7 exposure instead of brief or intermittent exposure. Given the fact that this is an automotive environment, I'd also wonder about seals, gaskets, etc.

    It's surprisingly common to see assembly notes on PCB prints calling out the use of silicone epoxy to secure bulky components (including switches and relays). I suspect that adding adhesives is sometimes done in a rush late in the design cycle after a product fails vibration testing.

    EEs do have a tendency to forget about contact wetting currents (source: I are one, and I do forget about them), but we're even less familiar with chemistry. Try finding wetting current specs on a relay datasheet. They're usually there, but buried. Now try finding the warning about not exposing the device to silicone. That's usually buried in a app note somewhere.

    1. Anonymous Coward
      Anonymous Coward

      Re: smells like

      "That's usually buried in a app note somewhere."

      It's printed *inside* the cardboard box, next to the discount offer on your next purchase. (The offer expires tomorrow)

      1. Rich 11

        Re: smells like

        ...and behind the sign saying 'Beware of the Leopard'!

    2. paulll

      Re: smells like

      Or silicone grease used to lube and corrosion-proof the pedal hinges while doing minimal damage to plastic/rubber parts and drivers' shoes...and globbed on very near the malfunctioning switches.

    3. Orv Silver badge

      Re: smells like

      My theory is Armor All. Dealerships *love* to prep car interiors with Armor All because it looks so shiny. (Makes the pedals slippery, though.)

      1. paulll

        Re: smells like

        Armor-All's probably equally plausible.

        But having owned a few North American vehicles of the 'his' variety (ie, manual), and forced to get up and under there with a torch to find and short the stupid clutch interlock switch, some cars look like an,"Alien," nest up there, and I'd guess it's silicone grease for the reasons mentioned above; I'd be surprised if some of the stuff *didn't* wind up where it's not meant to be.

  9. Mike 16

    Young'uns and switches

    Concur with the various mentions of minimum current. Once was a time when _serious_ switch interfaces made sure the combo of pullup resistor value and the B+ on the other end kept things shiny :-)

    But it's not just the folklore on electrical stuff that gets forgotten/ignored. After several sessions of an EE lying through his teeth about a particular switch being readable at all (despite being on the 10th bit of an 8-bit port), I got to confront the physical design. The ME had used a stamped lever to bear directly on the little button of a PCB-mounted microswitch, rather than the must-be-50-years-old practice of having something with a bit of compliance between the fragile, low-travel switch and the big-bad-world of industrial equipment. But by the time I could get anybody to listen (Go away, Gramps, you're just a programmer), it was too late, so they just edited the spec-sheet to no longer promise any mitigation of that particular failure mode.

  10. Ken Moorhouse Silver badge

    the rear brake lights not illuminating.

    Surely the solution is simple: Ensure that when transporting cadavers they are kept on the back seat, not in the boot.

    Or am I missing something?

    1. Korev Silver badge

      Re: the rear brake lights not illuminating.

      That's brazen... Most BOFHs around here opt for a roll of carpet and quicklime...

      1. Anonymous Coward
        Anonymous Coward

        Re: the rear brake lights not illuminating.

        We use Visqueen for the victi- I mean, cadavers here, helps keep down leakage and reduces the need for air fresheners with siloxanes.

    2. Eddy Ito

      Re: the rear brake lights not illuminating.

      Who would put them in the boot? You'd need at least one in a seat so you could drive in the HOV lanes.

      "Yes officer, I understand. It's just that I didn't see where law says the second occupant has to be alive."

  11. Korev Silver badge

    Another possibility?

    Could the source of the silicone be... Bulgarian Airbags?

    Silicone or leather? Who knows -->

  12. imanidiot Silver badge

    Sure, blame the customer

    I have a hard time believing the output from the cars occupants (no matter how noxious some people can be with their creams and perfumes) can affect a brake switch that low down in the car, in a usually well ventilated (by the lower heating/ventilation ducts) area. More likely it's something used in the fabrication process, combined with a poor switch design (as highlighted above).

  13. x 7



    two most obvious sources

    1. John McCallum

      WD 40

      has never contained silicone don't know about Duck Oil.

      1. Mike 125

        Re: WD 40

        >>has never contained silicone

        until now.

  14. Flywheel

    Methane Gas?

    I take it that they've not issued a directive about not farting in the affected vehicles? Mind you, the potentially flammable nature of farts offers a potential contact cleaning effect if flashpoint can be reached...

  15. Anonymous Coward
    Anonymous Coward

    DOT 5 silicone?

    Isn't there a sort of brake fluid that is silicone based? I think it is DOT 5? I can imagine that if it is (perhaps mistakenly) being put in the brake system, it might creep into the switches.

  16. Anonymous Coward
    Anonymous Coward

    I can't believe that no-one has yet twigged, that when they say 'shampoo', they mean Car Shampoo, not human shampoo...

    It's the silicone in the shinier and waxier cleaning components and that is surely what is doing the damage, not the shampoo of the passengers....

    1. Rich 11

      Don't spoil it. We're having fun.

    2. Anonymous Coward
      Anonymous Coward

      "not human shampoo..."

      Quite possibly. I've seen some of the hipsters who drive Subarus and I doubt their hair has ever been in the proximity of a cleaning product.

  17. Tom Paine

    "silcon gas"?

    If the brake light switches are being damaged by silicon gas, that car's running a little hot -- 3265 deg C it says here...

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