Loud popping sound under the dash

[chickman]

2002 Trailblazer has a loud popping sound under the dash when started. It pops about 5 or 6 times and then quits. I think it may be related to the climate control since the upper vents don't work sometimes.

[billqual]

Mine did that when the mode door motor stripped the gears.

[Reidster]

I'm having the same problem. Just stopped by the dealership this morning and was told that because the problem is intermittent, they couldn't do anything until "I" could tell them what causes the noise, LOL.

Maybe this post is enough for them to investigate the mode door motor gears.

thanks,

[keithandmarg]

My 2002 trail blazer was doing the same thing but also not every time it is funny that the dealership knew exactly what the problem was and fixed it. It was the actuator cam that was shorted. Unfortunately my car was not under warranty. It cost a couple of hundred dollars to fix. Could this be a possible recall in the future?

[Reidster]

Keithandmarg, be sure to keep your receipt so you can recover if there is a recall in the future.

I found a way to recreate the noise by changing the air mode from dash to defroster then back to dash again. When I brought it back to the dealership I complained that they could have been able to troubleshoot the problem but didn't even try. Thanks to this bulletin board I was able to diagnosed the problem on my own.

[drjimbo]

mine is doing the same thing. can I buy the "actuator cam" and fix it myself? Also, what is the actuator cam and what does it do? Thanks

[tom3]

Funny how, when the warranty is out, these dealers get really capable of finding and fixing these things.

[chuben]

I'm glad I'm not alone on this issue. Mine started making the popping sound recently. When I turn the key to on position it pops approximately 4 or 5 times. It's definitely coming from under the dash. My Trailblazer is a 2002 and has 39500 miles.

[ReefShark]

I took my '02 Trailblazer to the dealer last week to have the clicking repaired. From the posts on this thread I figured it was the actuator cam. The dealer confirmed that.

I was hoping that my extender warranty would cover the repair, but as usual, this part was not covered in the Gold Plus, only the Platinum.

Since the diagnostic service (needed before we could find out that it was not covered) had cost $78, I decided to bite the bullet and have it repaired.

The actuator cam was stripped.
Labor to pull the dash and replace the cam: $453.60
Part: $52.83
Total: $506.43 (GULP)

While we were already there, dash pulled, I had them check why I did not have speed 5 on the fan control.
Result: Test and replace Blower Resistor.
Labor: $113.40
Part: $27.79
Total: $141.19
Total for the day (not including rental car) : $647.62

Needless to say, not real happy, but there is no way I felt I could pull the dash.
Hope this helps and good luck.

[haynewp]

I just took mine 02' trailblazer in to the dealership to find out what that noise was. They said it would be $640 to replace the mode door actuator. I got them to fix all the other things that were wrong but, I am going to take it by somewhere else, it sounds like most of the cost is the labor for this part.

[4*wheels]

I see from the postings and replies that this is a prob. We just purchased an '03 TB and we have no heat on the driver's side. The passenger side heat is fine. Our dealer said that this prob. sounded like a actuator cam in the control module inside the dash that is part of the hvac for this vehicle. Unfortunately we can not say if it was popping before or not, it appears this was out before we even purchased. My question to all of you that previously posted; "Did you have loss of heat or a/c on either side?" Thanks.

[tom3]

Originally Posted by Reidster

I'm having the same problem. Just stopped by the dealership this morning and was told that because the problem is intermittent, they couldn't do anything until "I" could tell them what causes the noise, LOL.

Maybe this post is enough for them to investigate the mode door motor gears.

thanks,

Think recalls are for safety repairs only, for this type defect you're usually on your own. Would be interesting to see how many of these are actually failing early.

[chuben]

Originally Posted by chuben

I'm glad I'm not alone on this issue. Mine started making the popping sound recently. When I turn the key to on position it pops approximately 4 or 5 times. It's definitely coming from under the dash. My Trailblazer is a 2002 and has 39500 miles.

Well, I finally broke down and took my TB to the dealership to have my actuator cam replaced. After reading the other post I was prepared for the worst, but it wasn't near as bad as I expected, labor was $70.00 and the cam was $52.96. This made me a happy camper! :-)

[leachman74]

I had the same problem, on my 2002 Trailblazer. After having the vehicle about six months, the popping would only do it while starting, lasted about five minutes. Vehichle still under warrantee, the dealership tought at first it was the blower. They replaced the blower. The popping noise continued, a capable mechanic recognized it right away as the actuator. The actuator was replaced. About 1 1/2 years later and Now that my vehicle is out of warrantee around 40k miles, I got the same problem again. However much more intermentent right now. I brought it to the dealership, they said they couldn't identify it since it didn't do it while it was there, I told them to look at the service report at the work on my TB and they wouldn't listen to me.
They also told me it would be at my cost. I think a little more then $200 not sure about that price. I been living with it for more than 5k miles, kinda starting to really bother me. I don't think the mechanic is pulling the dash to repair this one, that is just a scam to get more money out of you (YOU KNOW, LIKE BODY SHOPS DO YOUR INSURANCE COMPANIES FOR REPAIR WORK). I'm going to see if Chiltons has come out with a repair manual on this, and hopefully I can find an aftermarket actuator. Thier italian version doesn't seem to be working too well. I think I'll make the repairs myself on this one.

[drjimbo]

I am sure this actuator cam needs to be replaced on my 2002 TB also but mine is also past the warranty. I think I'm going to try and get the part and replace it myself. Does anyone know the exact name of the part or part number and where I could buy it from. Also, does anyone know where it is located on the vehicle and how hard it would be to cahnge. I looked in Chilton and could find no help. Thanks