Ventilation System Noise

[CheezyBrit]

When my ventilation is not in the recycle air mode there is a rythmic thump under the passenger side dash. Anyone know what causes it. Also got the fuel gauge letter from GM just as mine broke, anyone know the cost of that repair?

[Dragon2U]

Originally Posted by CheezyBrit

When my ventilation is not in the recycle air mode there is a rythmic thump under the passenger side dash. Anyone know what causes it. Also got the fuel gauge letter from GM just as mine broke, anyone know the cost of that repair?

The rhythmic thump is likely a broken recirculation door motor. The plastic gear breaks a tooth in the and the motor continues to try to position itself. It's a $45 part but will cost several hundred to get repaired at the dealer due to having to take the dash apart, disconnect AC and empty the radiator. I think someone on here said the shop rate was around 10 hours?? Myself and a few others have replaced it at home in a few hours. If you have good dexterity and some patience it can be done.

Not sure about the fuel gauge problem unless it is the tank sending/pump unit? I just replaced one on a Silverado a few weeks ago, part cost was about $200 but I have seen them as high as $400, took about 2 hours to do but "shop rates" may be longer. I've been told that they tend to have longer life if you keep the tank filled near or above half at all times but I think they just like to break. Could also be the speedometer cluster, if it is, spend a few extra $$ to replace all the indicator motors with the new design that doesn't have the breakage issue. The motors are only a few dollars apiece and take about 1 hour to replace, most speedometer services charge around $50 to repair.



Good Luck

[Bagger]

Originally Posted by Dragon2U

The rhythmic thump is likely a broken recirculation door motor. The plastic gear breaks a tooth in the and the motor continues to try to position itself. It's a $45 part but will cost several hundred to get repaired at the dealer due to having to take the dash apart, disconnect AC and empty the radiator. I think someone on here said the shop rate was around 10 hours?? Myself and a few others have replaced it at home in a few hours. If you have good dexterity and some patience it can be done.

Yuk...Tearing a dash apart the first time can be a pain. Usually end up breaking a few of those supposedly re-usable fasteners. And once you get it back together you have squeaks/rattles you didn't have before.

[twooldfarmers]

once I had my dash apart for the first time I did not replace the two lower nuts on the air bag module.

not necessary either for safety or rattles as it was real tight with just the top two and should the air bag ever come into play it is pushing back against the frame in which it is held so it will function as required.

...but you still have to get those nuts off the first time, it helps to have one of those flexible inspection mirrors and a long neck flexible LED inspection light such as you can get at Harbor Freight so you can locate them first and then go after them with the 1/4 drive socket tools. It takes a while.