Automotive Column 31 Noise in Dash
Syndicated Newspaper Column
Since most vehicles have now gone to all electric HVAC system door controls using motors and sensors along with a processor to operate the system there are many things that can go wrong behind your dash. Knowing a little bit about the system can help to isolate the noises.
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Dear Motor Medics,
I have a 2005 Chevrolet 2500 truck with a 6.0 engine and automatic transmission. Lately I have been experiencing a noise behind the dashboard upon starting. At first I thought it was under the hood and searched for something that could make the kind of sound I was experiencing. After much searching I discovered it was coming from behind the passenger side of the dashboard. It is located just to the right of the glove box door and back by the firewall. There is a box there that I assume is part of the heating system and when I touch it I can feel the clicking in sync to the noise. This noise occurs each time I start the vehicle and lasts for about one minute. Have you ever heard a noise like this before?
Scott in Denver Colorado
Yes we have heard this noise before and can help you. Most vehicles went to fully electrically operated heater door systems in the late nineties. The door motors have position sensors in them and when they fail the computer does not know where the door position is. Because of this failure the door motor keeps moving when at the end of its travel and begins to strip the gear teeth causing the noise until the module shuts it down at a pre-determined time limit. To fix the noise you will likely need a new door motor. Thanks for the email Scott.
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.