A/C Blower Fan Intermittent

[moesee01]

I have a 2002 I35 that has an intermittent Blower Fan motor. If I start out my trip the blower fan is working fine. Then I'll stop once and it will come back on again. If I stop a second time, it may or may not start up again. My fan indicator shows the fan working at the proper speed, but no air is coming out. Then I'll get it home and let it sit overnight and in the morning it'll start working again. This happens about once a week now. It used to happen about once a month a few weeks ago.

Any ideas?

[loystock]

Welcome to NICO.

Problem is most likely due to loose/dirty connections. Check/re-seat Blower fuse, blower connector and Fan Control Amplifier. Apply dielectric grease on the connector pins/sockets. Refer to the link below, starting on page HA-66 for Blower Diagnostic and HA-67 for Component Location and Schematic Diagram.

http://www.nicoclub.com/FSM/i35/2002/ha.pdf

[moesee01]

Thanks for the truly enlightening answer. Would you happen to know how much a local mechanic would charge for something like this? How long it should take in other words?

[sunny50]

I have the same problem. After thorough research on this site I found this to be a common problem on I35 and other infinitis/maximas.Blower motor gets dirty and is overworked on these vehichles which leads to the fan control amplifier overheating and going bad. To find more info do a search of "darlington" for the fan control amplifier switch and "blower motor" for the motor itself. I plan on replacing replacing both the motor and the fan control amplifier(darlington switch). I will probably replace the cabin filter too while I have everything apart anyway.Good luck.

[moesee01]

Thanks for the input. Have you determined what it will cost to fix what you suggest?

[sunny50]

Looking at about $200 in after-market parts if I do it myself. No idea what a dealer would charge if they do it, but I figure their labor time should be no more than 3 hours. Further searches of this site will give you very detailed instructions on how to do it,including pictures. Sorry I can't post a link for it,but I don't know how.

[sunny50]

Finally got time to take everything apart. Blower motor seemed ok so I diidn't replace it. I replaced fan control switch(amplifier), blower motor relay(located behind glove box,right side), and the cabin air filter. Everything works fine now! My guess is my problem was the fan control switch. Replaced relay because it was easy to get to at that point. All of this took me about 2 hours to do just taking my time(I tend to over-think things). Also, the cabin air filter was VERY dirty and probably caused the blower to work harder than it should, which led to the fan switch over-heating and burning out. Moral of story: Be sure to make changing cabin-filter a part of your routine maintenance. I would change it at least every 30,000 miles. Fan cotrol switch cost me $106 from a local Infiniti dealer, but you can find them much cheaper online(about $60-$70). Relay and filter I got from autozone for $45 total.