I35 HVAC blower fan problem

[burnsilver]

Hi, All.

I own a 2003 i35 and am having a problem with the blower fan that circulates the air through the cabin vents and defroster vents under the windshield. Other than the fan not blowing the air, the system appears to be in working order. I haven't had one problem with it up to this point - no strange noises, etc. The fan stopped working the other day, so I did some research and decided to try replacing parts myself.

Here's what I've done so far: I replaced the fan control amp yesterday. The fan worked perfectly for about 5-10 minutes with the new fan control amp, then it stopped again. When I finally got to my destination, I checked the part I had replaced and it was quite hot. Here's the part I replaced: http://www.compressorworld.net/ecommerc ... h-atc.html

I suspect that some other malfunction in the blower fan system is causing some sort of increased load on the fan control amp, so do any of you have some advice on what to look at next?

Thanks for any help you can offer.
Sincerely,
Paul
Fresno CA

[MaximA32]

First, welcome! Second, is the fan blowing at the same speed no matter the speed you turn the knob to?

[burnsilver]

Thanks for your response.
Yes, all four of the little blade icons work on the fan speed display, but the control has no effect. I would even say that the fan isn't functioning at all - not even at what would be the low speed under normal operation.

Thanks,
Paul

[MaximA32]

Sorry it took so long to get back to you Paul. It sounds like it's the blower motor resistor. It's fairly easy to replace and should be located in the passenger side foot well right on the blower motor housing. If you pick the part up from a local Autozone, they should be able to give you a picture with the location of the part.

[burnsilver]

Hi. Thanks for your help, but I'm a little confused (but I don't know much about cars). Is there another part different from the fan control amp that is called the blower motor resistor? As I noted above, I replaced the fan control amp and it burned out in about five minutes.

I took it in to a shop and they put some kind of meter on the fan motor to see if it was drawing too much current. They said it's a little out of spec at high speed and might be pulling so much at lower speeds that it's burning up the fan control amp. They wanted a lot of money to do it, so I ordered two parts online - another fan control amp and a new blower motor. My plan is to replace both of those myself and hopefully solve the problem.

I am unaware of a different part that would be causing the fan control amp to burn up in just a few minutes other than a bad fan motor, but if you know of anything else, I'd like to just replace that part, too, before I burn up another $100 fan control amp.

Thanks again for your help.
Paul

[burnsilver]

FYI, I changed out the fan blower motor and the fan control amp last night and so far, it's running great after about 40 minutes of driving and running fan at all different settings.

If anyone else has this issue in the future, what I think might have been the cause of my problem was the in-cabin filter behind the glove compartment. It was VERY dirty with small leaves and other debris in it. The car is coming up on 10 years old and it's never been changed. What I think may have happened is that it was causing so much resistance to the airflow that the fan was drawing more current and burning out the fan control amp.

Don't know if that is really what happened, but it seems logical.

So, I've learned that I'm going to change my filter regularly and hopefully avoid this issue in the future.