Click , click

[Bowed]

My 99 tahoe makes a rapid clicking noise under the dash when the fresh air vents are turned on . If I select defroster the clicking stops . Is there a relay for the vent doors and exactly where is it located . Thanks.


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[Jimbotronics]

I had the same issue on my avalanche - it was driving me nuts. Turned out to be the air temp actuator (the dial that goes from cold to hot). When it starts making the noice move the selector one notch or two up from cold and see if it stops. If it does there's your problem, if it doesn't I wasn't of any help...

[Bowed]

Did you replace anything ? The temp switch did make some difference along with the inside / outside air button when I tried them . On pulling stuff apart I found all the controls - fan speed , temp and vent switches , air in / out and AC on / off buttons , are all part of one printed circuit board assembly . I kept tracing until I found a small metal box assembley on the duct between the blower motor and inside firewall . This black box has a small electric motor , several gears and another printed circuit board . It was tripping the air door , making it jitterbug which was the clicking noise . I disconnected it ( a real b!tch job ) and no more clicking noise but would guess the door is set on outside air . Thanks for the heads up .


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[Jimbotronics]

I actually haven't replaced mine yet, just know what's causing it. Luckily, it's still under warranty just hadn't had the time to take it in. The way the guy explained it it's the switch causing the actuator to jitterbug, the acuator is recieving open/close messages. I plan to get it in next weekend and I'll let you know what they replaced.

[Huck]

Unfortunately the heater/AC/Vent design on these trucks sucks big time. Every one I've talked to and my personal experience shows the the actuators up under the dash tend to go kaka. The dealers charge like $600.+ to fix as they need to drop the dash down to fix anything!!!! If you can change anything from under the dash, that is a big plus!!!

[Jimbotronics]

Huck is absolutely correct, I just called to schedule mine so I asked the question of exactly what they'd be replacing. He said dropping the dash and changing out the actuator. Then I asked what the expensive would be if I was paying for it. He totaled it up at $843. Definitely something I would be living with if it wasn't on their dime.

[Bowed]

Wow $843 , thats crazy . I got mine out without droping the dash or duct work but only because I have small to medium hands and was able to work both hands up into the duct work and then use a mini ratchet to slowly work the 2 screws out that hold the actuator . A very , very difficult job . I have no actuator in there right now and I think it's throwing the system off because I can hear the speed of the blower change for some reason , like maybe another door in the system is opening and closeing . I am becoming more disappointed with the way chevy is building trucks now . Some of the parts I have purchased lately have run 5 to 7 hundred dollars handed over the counter . Didn't even ask how much installed .


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[Jimbotronics]

Maybe there's another actuator further up? Don't know. But yes $843 is nuts, I wouldn't be paying it. My biggest concern is that they f* something else up doing the job. Had my wifes car in for annual maint earlier in the week, when I got in it to leave the music volumn was up so loud I 'bout jumped outta my damn skin..

[Jimbotronics]

The dealer called me within just a few hours of dropping it off. Turned out it was the lower actuator (he said there's three) - Luckily they didn't have to drop the dash...woohoo! No mo clicking...

[Bowed]

Thanks for the follow up info . The one I took out to stop the clicking must be the same bottom actuator. I did figure a way to delete it without throwing the PC boards out of wack . Thanks again .

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