Hello all,
The A/C blower fan is not blowing at all. Obviously, this is going to be a serious problem when it gets hotter and when it rains and I have no defrost ability. Here are the (maybe) pertinent facts:

1) There is A/C, since I do get a little cold air when the car is in motion and fresh air is coming through the vents.
2) The 2 fuses are fine, I even switched in the spare for each of the fuses, and they visually seem fine.
3) I have removed the glovebox and measured the voltage going into the blower fan while the car is running and the A/C is on. There is voltage across the leads going into the blower. This voltage changes as I change the fan speed on the A/C control (i.e. electronic buttons)
4) There is NO voltage on the middle wire (I assume that this is a control wire) that is between the two power leads into the blower fan
5) There is a finite electrical resistance in the blower fan, so I am assuming that the motor is not shorted and should be fine (just an assumption on my part)
6) I am also having faulty tire pressure sensors (coincidence or connected to the fan problem?). The TPS indicator blinks 57 times on the dash then remains fixed. I measured the tires, and the pressure is fine in all four (~35psi)
7) All these problems started after a very heavy rain from last week which flooded the passenger side of the car. The working theory is that there may be a very small gap in the windshield which I had replaced by Safelite several years ago and the rain leaked into the area behind the glovebox where all the electronics and the blower itself are located.
8) The control wire appears to lead back directly to the engine control unit (ECU). I wouldn't believe that the ECU was damaged since it appears to be well sealed and the rest of the engine seems to be performing fine. Of course, this may be wishful thinking. There are no error codes from the computer.

Any help on how to fix this problem without going to the dealer (which probably lead to a repair bill north of $1000) would be greatly appreciated!

Thanks,

Adam

 

I had the same problem occur to my car a couple of weeks ago however since we just got a lot of snow here in CO I havent gotten around to fix the issue. My recommendation... just go fast. I mean your AC will just diminish racing performance so best to leave it off.

You can also try these solutions:
http://www.wikihow.com/Cool-Yourself...r-Conditioning

Have you thought about portable air conditioners?

Your Buddy,
SUPAFASTG35

 

HI Adam, do you have the shop manuals? If not here is a link courtesy of another member:

http://www.sfplayers.com/serviceManuals/

the HAC section has some steps for diagnoses and inspection around page 88. There's a lot to read but it walks you through taking voltages and moving onto the next steps. That third wire may be for the magnetic clutch on the fan motor (i'm getting that impression from what i'm reading in that section). It may not be engaging for whatever reason. Have the radio run the self-diagnosis software, that may tell you right away.

https://g35driver.com/forums/g35-sed...stic-mode.html

This is also found on page 51 of the HAC section.

Bob

 

Remmy,

Thanks for the heads up on the manuals! Definitely gives me a place to start. I'll also look into the diagnostics.

Adam

 

Hello Adam,

My name is Sarah I am with Safelite AutoGlass if there is something I can help you with I will be happy to. Please call me at 866-212-5457.

Thank you
Sarah Powers

 

Sarah,

Thanks for offering your assistance in this matter, it is much appreciated! I will gladly get back to you regarding the windshield after I resolve the immediate issue of the blower fan electronics.

I look forward to speaking with you.

Adam

 

OK, finally got to the bottom of it. In short, I replaced the fan, and all is well!

But, it wasn't an obvious fix. There was no indication that the fan shorted since I measured a finite ohmage across the leads. But when measuring the signal voltage using an oscilloscope, a regular adjustable (by fan speed) pattern was measured. The amplitude was about 20mV. This explains why the multi-meter never picked it up.

So at the time, I thought it was about equal probability that the problem was the fan or the unified sensor/AC amplifier. I found a *used* fan on Amazon for $30! Even though it was for a Nissan Altima, it was the same model. So for $30, and probably returnable to Amazon, I took a shot with it, and it work like a champ!

I also had Safelite come and inspect the windshield that was installed, which I thought was the cause of the leak. As it turns out, the technician told me that this problem is common and usually not due to windshield installation. Rather, underneath the trim beneath the wipers is the air inlet to the cabin. It is a 3"x3" hole in the sheet metal with a ~3" tall plastic shroud surrounding the hole. The shroud is joined to the sheet metal with two screws, but the rest of the perimeter of the shroud is pretty loose. It is very possible that some water could get beneath the initial trim, leak under the shroud and work its way through the cabin air ducting and accumulate in the fan where it could damage the fan circuitry.

I'm surprised that the cowl is designed this way. Using a little bit of plumbers putty should solve the problem.

Thanks again for everyones help, especially the manuals.

Adam

 

Glad to hear you resolved it for cheap!!

 

Hi am Camille

2003 g35 coupe....the Ac compressor will not come on when connected directly to connections...but when connected indirectly (straight from the battery) it works and cools really well...the electrician made is check and diagnosed everything in good working condition...but the compressor still not coming on....can u help

 

Camille, you posted this in the 2nd generation G35 technical section. You will probably get better results posting it over (here: https://g35driver.com/forums/general...questions-189/ ) in the 1st generation G35 technical section

 

My blower would sometimes work. Often it would start out the drive not working then I'd go over a bump and it would blow again. The AC system was working and I could feel cool air pull through at speed with the rear windows cracked.

Anyway turned out it was the blower relay not the blower fan. $10 part or $40 from Infiniti.

This is a small blue relay at the back and bottom of the fuse/relay panel which is the blower relay. I didn't really understand the drawings in the service manual until I pulled it out. There are three plastic tabs which need to be depressed to free the panel so that you can get to the relays behind it. I didn't need to remove any connectors. I did have to remove the trim panel surrounding it - you can get to the fuses on the front of it just by removing the cover but getting to the relays needs a lot more room to work. Also release the footbrake!

Glad I started with the relay - it was cheap and relatively easy to get to.

 

THANK YOU! THANK YOU! THANK YOU!

Just fixed the blower with a new relay from NAPA. Took ten minutes and $35. Can't begin to imagine what the dealer would have charged

 

:-D It did run through my mind how much the dealer would have charged... probably would have been more than one visit because it's intermittent ... and they would have had it for hours... and they would have started replacing stuff......... for want of a $2 relay, $15 from Nissan, $35 from Infiniti... still saved $$$$