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part of this cycling is due to the fact that when the AC is on, the radiator fans kick in more often to cool the AC radiator that is in front of the engine radiator... usualy the compressor keeps on running during this cycling.
 

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Discussion Starter #42
mcampo said:
^^ That seems odd^^ maybe you have something wrong. That or you are confusing it with the fan which will cycle more often when running A/C. I dont know ...just a thought. I dont have an '03, but mine doesnt do that.
Shut up Mr. "I-have-a-2002-model-and-my-air-conditioner-isnt-retarded-like-all-yours-are-haha!"

Hehe just kidding man, I envy your '02 A/C :D
 

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Discussion Starter #43
metalhead said:
so basically when this auto-ac turns on the ac stays on the whole time, but it cycles on and off periodically....meaning, the whole time this auto-ac is on, the car is slower cause of the AC..
Pretty much yes, unless you mash the gas, then it shuts off like it's supposed to. But for moderate acceleration it's amazing how much power it robs, even with our cars' torque.
 

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lol....didnt mean to rub it in....:) Good information to know. I like the threads where we can really break it down and isolate the problem or issue at hand.
 

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I'm fairly certain the cycling on/off is not the fans(s)...I know their sound, and fans turning on don't pull the RPMs down at idle the way the compressor does.
 

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A couple of points:
1. Turning your vent control knob to defrost will not, by itself, turn on the A/C compressor. The compressor will not go on unless the fan is on also.
2. Nissan thinks we are all stupid. Why dont they just say in the manual "For maximum defrosting, turn the vent to defrost and turn on the A/C". Let us decide if we want it or not!
 

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cscade said:
Shut up Mr. "I-have-a-2002-model-and-my-air-conditioner-isnt-retarded-like-all-yours-are-haha!"

Hehe just kidding man, I envy your '02 A/C :D
my 2002 spec-v's a/c acts the same way my 2003 spec-v... maybe he just as a factory freak, or it's always over 65 degrees where he lives... ( in that case it's not suppossed to come on when in defrost mode)
 

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Does anyone have the A/C wiring diagram from the FSM for the '03. I would love to see how the defrost micr-switch is hooked up.
 

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You just have to cut the 2 wires going into the switch, skin it and wire them together like this:


This is according to the FSM (no matter which year/trim, it apply to ALL B15). The picture was post in the original thread of the A/C, post by me long time ago. The link is in the first post of THIS thread. You see that when the microswitch is off, the current CAN pass, so get the 2 wires together get rid of the microswitch. Here is the image:


What differ from year to year is like on 03+, once the defrost as been selected, the A/C kicks in and STAY ON until you turn off the car and choose another vent zone (or if fan is set to OFF, of course). On 02-, you can put the zone back to somewhere else than defrost and the A/C will shut down. Read your owner's manual for details on your car year.

Hope it help!
 

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If that's the diagram for an '03 then it makes no sense that the A/C would stay on after switching out of defrost mode but not stay on when turning the A/C button OFF. The defrost micro-switch and the A/C switch are wired in parallel. The ECU can't tell which switch is "ON", both are wired to the same signal input.
 

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I understand exactly want you mean but unfortunatly, to my knowledge, nobody here have the 03 FSM to compare. Maybe the schematic also are not 100% exact and hide some little details from us.

But thrust me, I have a 2003 Spec-V and before I've done the mod, once the A/C was activated by the microswitch, it will never shut down. The A/C button, on the other side would work fine and shut down the A/C normally. And after the mod, even on a 2003, will never kick in the A/C automaticly on defrost.
 

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I had to go out and try it for myself. Of course, your're absolutely correct!

I'm doing the mod.
 

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Im sorry, but I just went and looked on my car. I have an 02 Spec V. I turned the car with no A/C. Compressor does not run. Turn the vents to defrost. Compressor not on. Turn the fan on, then the compressor turned on. As soon as I turned the fan off the compressor turned off too. I have motor mounts so i definatelt know when the compressor is on. And i looked at the compressor its self, the clutch was not engaged. I dont understand the benifit of this mod....
 

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OK i just read the above post, it is pointless for 02s. but it is good for everyone else. i guess im just lucky! hehehe
 

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edit....I take it back...just read your repost....
 

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The benefit is that you control whether or not the compressor is ON when in DEFOG mode. Doesn't matter what year you have. The "auto-compressor-ON-when-in-DEFOG" is particularly annoying on the 03 because the compressor stays on even after you switch out of DEFOG.
 

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Uhh.. my compressor and everything goes off and remains off when I take off the defroster... no need to restart my car.
 

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Discussion Starter #60
Wow, it's the amazing revival of the dead thread!

Everyone's still in disagreement over it too ;)

As for the schematic above, very useful, but it's obviously not correct for the '03. Something changed.
 
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