1992 1500 Knock

[mark1223]

Hello, I have a 1992 silverado 1500 that has a knock coming from under the dash. I purchased it this way, so unsure if anything may have fallen into the duct. I am thinking it may be the actuator, because it starts when I start the truck and continues for around a minute after shutting the truck down. I did not mind it, but now, im interested in the truck and was hoping to fix the problem. Thank you for any insight you guys may provide.

[Squirrely]

air in the cooling lines can cause a knocking sound.

 

just a thought

[mark1223]

This is a loud a$$ knock, that can be heard outside the truck from prolly 4 or so feet away. Im thinkin it actuator because, it does it when I also adjust blower level. ie head or feet. How hard is the actuator to replace in these trucks?

[Squirrely]

Easy part to replace.

It's electronically controlled and has a 3 or 4 wire harness. The motor should be located by drivers side of the tri-level box(or whatever it's called).

 

I just replaced my motor last month.

 

FYI, the new unit may not be indexed properly. You will need to make sure indexing (or stops) are correct on the new motor or it will try to run past the stops when turned to either full defrost or full dash.

 

hope this makes sense.

[mark1223]

Would it be the blower motor or the actuator?

[Squirrely]

I've never heard a knocking blower motor.

 

Either way, both of these are easy to reach and replace .

[mark1223]

I didnt think it would have been the blower motor, but you had me a little confused with the motor part. Would that be the door actuator, or if not, do you have a part number for the item? Thank you for all the help.

[mark1223]

I figured it out. It was the actuator by the blower motor. I just unplugged it and its fine now. saved me some $. Thanks for the help.