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Discussion Starter #1
Hello gang,

I'm trouble shooting my 2007 350z ac and here is what's happening. When I have the vehicle on, I turn the knob to any blower level and get nothing to happen. I press the AC button and i hear it engage on the AC clutch mechanism and I feel the vehicle working harder. Neither the cold or hot turn on initially but after 10-20 minutes driving the blower kicks on. The cold and hot at that time work fine but if I shut it off, there is a good chance it won't come back on.

I checked my low pressure freon with a kit and made sure it's serviced, which it is. I was looking into the FSM and the schematics but it doesn't look like the 2007 had a blower relay or I would replace that.

This all started two years ago but in the beginning it was rare that it wouldn't turn on and it would turn on faster after not initially starting, within 2 minutes. So over time it's gotten worse, any ideas? Thanks.
 

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Have you pulled any codes from the BCM? There may be some codes in memory that will help pinpoint your problem. Also, when did this problem start? Was it recently, or has been a problem from when you first bought the car? BTW- some mileage and history on the car might help.
 

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Discussion Starter #3
No codes have popped. I scanned it again this morning. Mileage 107,000. Car started doing this two years ago but it steadily became more frequent and started taking longer to engage the blower. Two years ago the blower started after two minutes and now it's at 10-15 minutes to start blowing. When purchased the vehicle did not have any AC/heat issues. I have owned the vehicle for four years.
 

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Discussion Starter #4 (Edited)
Here is what I just did in the last half hour. I read the AC blower motor connector with a multi Meter on pins 1, 2, and 3. According to the manual I should get 0.5 ohms good ground on pin 3 which I did. I went pin 3 to vehicle ground and read perfect. I read pin 1 to vehicle ground, which pin 1 is ignition battery power and I get good power. I tested the ac control unit by unplugging the center console AC unit ribbon. If I remember correctly unplugging that should cause the blower and heat kick on Max. Though nothing happened when I started the car, still no air blowing. I'm starting to suspect my ac blower motor of being internally faulted in some way.
 

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Discussion Starter #5
It's a $150.00 chance on an electrical part that O'Reilly's and AutoZone won't let me return, only exchange for another warranty item. I wanna exhaust all trouble shooting methods before I take that chance.
 

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The other option is to take it to a Nissan dealer and have a trained tech with a CONSULT III diagnose the problem. They can install an OEM blower motor and if that's not really the problem, find what the real issue is. Sometimes you just need to bite the bullet and get it fixed.
 

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Discussion Starter #7
Update: I installed a new blower motor but the problem persists. The last two things I can truly consider is the AC relay in the engine bay behind the battery box but I don't think that is the problem from the fact that the power was available at the connector at 15 volts. I get 15 volts with the blower not blowing so I think I'm going to run the car until three blower comes on and read voltage then. If voltage is higher than I can consider the relay.

My best guess after that point is the AC controller in the center dash. Perhaps it's internally faulted because it works over time. It clicks on the AC clutch but maybe doesn't send a signal to the blower motor. I'm still open to any trouble shooting ideas guys.
 

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Discussion Starter #8
Ok I found a huge clue to my issue here http://www.350z-tech.com/forums/123-maintenance-repairs/72151-ac-problem-help.html

I'm going to run a new wire from the AC controller connector in the dash to the blower connector. Also looks like my issue is specific to the harnesses of 2006-2008 350z rev up and Hr models. I will post my findings next weekend when I rewire it so that the community can have some closure.
 

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Discussion Starter #9
I rewired pin 2 of blower connector to the unified ac amplifier in the center dash pin 53 and the blower still didn't engage. Then I went to pin 2 of the blower connector and vehicle frame ground to test the knob itself on the fan through all models manual. I turned on the car and the AC while cycling through all the fan settings, the numbers changed as they should so that ruled out the unified ac amplifier per the FSM. I'm officially out of ideas so time to sadly bite the bullet and put the car on the dealerships consult III system and see if it finds electrical harness issues. I'm going to have to wait until I save some pennies since that diagnosis is $160.00 to just run it with no repair.

I pride myself on doing all repairs and modifications myself but looks like this time I've been bested and I'm pretty bitter about it. Over 12 hours of trouble shooting to still not know. All I do know is that it's not refrigerant, a fuse, the blower, the unified ac amplifier, the AC compressor or the AC clutch. How frustrating.
 

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The automation in vehicle operating systems can be pretty complex, and the 350Z is pretty old (in comparison with 2018-spec). No need to get down- you pushed hard- much harder than most and came up empty. Maybe you'll learn something from the diagnosis.


One other suggestion: check if any of the dealership techs do work on the side. Some do, and charge quite a bit less if you arrange to work with them.
 

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I’m in the same situation. I’ve replaced the blower motor and the control unit, but still nothing. What did the dealer determine was the issue?
 

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It's been months since the OP has even logged on. I wouldn't hold out much hope of an answer, as it appears the Admiral has sailed on.
 

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Discussion Starter #16
*Update a year and 8 months later*

I have dropped off the vehicle to the dealership to get their diagnosis with the ac electrical system. A big part of me thinks the FSM schematic is incorrect and there is something not being drawn correctly. Either way I know the cost of this repair will likely be around 700 bucks but I'm honestly doing it so we can have an answer for the future. It's strange how no one on the internet has figured out this issue yet but hopefully I change that today. The car has been at the dealership since yesterday and I hope to get good news and a large bill today. Sorry for the delay everyone but deployments happen in the military and priorities change.
 

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Discussion Starter #17
Dealership called. The issue was indeed a relay somewhere underneath the drivers side electrical panel. When I investigated that area 5 times I never saw such a relay. I told the dealer that I want the old part and exact location when I arrive. I suspect that the schematics for the 2007 and 2008 350z do not observe this relay and no one has shown me its location yet online for this year group. A $525 dollar bill due to questionable schematics and a mystery relay. My loss is your gain everyone with an HR. Please once I get the pics and details up, be sure to spread this knowledge to others so they can spare themselves this 3 and a half year head hurter.
 
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