Knocking sound in passenger side dash

LAVADA GAMBOE TAYLOR

MEMBER
2000 CHEVROLET SILVERADO
1.5L
V8
4WD
AUTOMATIC
227,000 MILES

When vehicle is on there is a knocking sound, like a woodpecker, in the passenger side dash. The sound does not change when adjusting temperature controls.
There is a fainter winding noise that can sometimes be heard between knocks.
I suspect it’s an actuator based on research, but it would be nice to know which one before disassembling the truck.

3 Replies

KASEKENNY

MECHANIC
18,907 POSTS

You are correct that this is most likely an actuator. Unfortunately there is no way to know for sure which one this is unless one of them is not operating. Like if you are not able to change the temp then it would be the temp actuator. Or if you can't change position, it would be the mode actuator.

I at attaching the process below for the mode and temp actuators. they are basically in the same area so it is not that big of a deal if you are not sure. You can just access them and then put you finger on them when they are clicking to tell which one it is.

Also, here is a guide that talks about this as well:

https://www.2carpros.com/articles/replace-blend-door-motor

Run through this material and let us know what questions you have. Thanks

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