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Old 01-26-2006, 09:31 PM
2000CAYukon 2000CAYukon is offline
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Re: HVAC problem, loud knocking!

Quote:
Originally Posted by mrlaji
I have a '93 Chevy Silverado 2500 that has an embarrassing problem. Every time I turn off the ignition (or on), there is a loud knocking sound coming from inside the dashboard. It sounds like a little guy inside there banging away with a hammer on the dashboard, and is loud enough that people turn to look.

It also does the same thing when using the heater (or AC) and I press the "MAX" button. It does switch from external to recirc (or vice versa), and then the knocking starts, lasting about 15 seconds.

Any clues as to what is causing the problem?

Thanks,

Robin
Sounds like something is hitting the cage that the blower motor turns. I would pull the blower motor to take a look and go from there.

//2000CAYukon
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