Automotive Column 28 Power Drains
Syndicated Newspaper Column
Vehicles have change electronically in many ways. While they have become better they may need to be operated a bit differently in some cases. Check your owners manual if you have a question about a system.
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Dear Motor Medics,
My question is about accessories plugged into a lighter socket. Recently I have been experiencing dead batteries on my 2009 Cadillac Escalade and they tell me it’s caused by the accessories that I leave plugged into the lighter at all times. If the vehicle is not driven every day it will not start and is completely dead. I question how something as small as a cell phone or GPS unit can drain a battery so quickly, is this possible? I have stopped leaving things plugged in and have had no further issues but wonder if it’s not just a weak battery. What are your thoughts?
Darla in Elmira New York
It may sound strange but when anything is left plugged into the accessory outlet it can run the battery dead. Yes the power drain is very small and would take many days to drain a battery but there is something much larger at work here. Newer vehicles have many modules that when awake (turned on) will draw several amps of power and would drain a battery very quickly. To prevent this drain the modules go into a sleep state just like a home computer in sleep mode. They know when to sleep by monitoring the systems for non-use just like a home computer. If something is being charged by the lighter socket they think the system is still in use and keep the modules powered thus draining the battery quickly.
Take care, the Motor Medics
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Advice given by the Motor Medics is for entertainment only. Each problem is different and requires different approaches and answers given here are opinions and just one possibility. Always follow all recommended safety procedures and consult with your own qualified technician before attempting repairs of any kind.