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Ignorance is Not Bliss


I have written previously how ignoring that little orange engine light can cost you more in the long run. A gas cap that doesn’t seal will turn that orange light on and leave it on. It won’t really ever cause your vehicle to run improperly though your vehicle is not as friendly to the environment as it should be. When that light is stuck on though and a poor air flow sensor is causing your vehicle to run lean (not quite enough fuel with the air) it may be damaging to your engine with no further information to you the driver. The orange light is on and now two things are wrong. The second one will cost a lot of money in the long run.

Warning lights being on are not the only thing that tell you something is wrong with your vehicle. Sometimes your vehicle may just not be functioning the way it should be. You may or may not notice but there could be ramifications to not knowing or not doing anything about it.

A common scenario these days is a broken switch in one of the vehicle’s door locks. Probably most common is the driver’s door lock. It is used the most.

Once upon a time these switches were in the door jamb. Open your door, the door moves away from the switch, the switch pops out and the interior light turns on to help you see as you get in the car. Simple. Close the door and the light goes out. Worst case scenario switch sticks on and interior lights stay on all the time and kills that battery. Gotta fix that. Switches were cheap.

Fast forward to the 21st century and most of those switches are integral to the door latch. That cheap switch is buried in a mechanical device that might have several electrical components. That switch may only be replaced by changing the whole door latch. Removing that door latch requires removing a door panel and maybe a whole electrical window windy system. Yes, a lot more time for labour and a lot more money for the part.

The customer may say they can live without interior lights turning on when they get in the vehicle. Some vehicles turn on the interior lights when you open the door locks with the key fob so the owner or driver might not even recognize the missing door switch.

The modern automobile uses that door switch for a lot more jobs than just turning on interior lights. It is integral to the vehicle network. The security system waits for a signal from that door being opened after the door unlock command is performed. If no doors are opened the locks are locked again after a certain amount of time. Have you ever noticed how the radio in your vehicle now stays on when you turn off the key? You can even remove the key and it does not turn off. Open the driver’s door though and the radio turns off. The switch in the door latch performs this function. Otherwise the radio will stay on for a period of time.

The signal from that one little door switch as you leave the vehicle initializes a powering down sequence within the vehicle. When that switch is not working the power down sequence is different. It takes way longer for all the accessories and computers to shut down. What suffers? Your battery and your alternator! You might be wondering why your vehicle’s battery just does not last the way it used to.

If you are driving a newer diesel or direct injected gasoline engined vehicle that door switch is used to make your vehicle start and run better. Yes, believe it. Opening the door in a direct injected gasoline engined vehicle will turn on the in tank low pressure fuel pump to insure the high pressure fuel pump has a good supply of fuel for starting. For a newer diesel engine it might perform two functions; turning on the glow plugs and the low pressure fuel pump.

Sure, the vehicle will start without this early initialization but wear and tear will be greater on the high pressure pump, the starting system, the battery, and the charging system. All expensive components.

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