Welcome to the North American Subaru Impreza Owners Club Saturday July 4, 2015
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Electrical & Lighting

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 08-28-2002, 09:13 PM   #1
whiterabbit
Scooby Specialist
 
Member#: 16755
Join Date: Mar 2002
Location: yo mama's house
Default preventing AC from coming on when using defogger

Is there a way to keep the AC from kicking in when you use the front defogger?
* Registered users of the site do not see these ads.
whiterabbit is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 08-28-2002, 09:41 PM   #2
Mulder
Trust no one
Moderator
 
Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
Vehicle:
02 WRX
15 WRX/05 GTO

Default

Mulder is offline   Reply With Quote
Old 08-28-2002, 09:56 PM   #3
samowrx
Scooby Specialist
 
Member#: 8403
Join Date: Jul 2001
Default

i've never noticed if the ac tunes on in my car with the defrost. i don't think it does. the ac light doesn't light up.
samowrx is offline   Reply With Quote
Old 08-28-2002, 10:02 PM   #4
Mulder
Trust no one
Moderator
 
Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
Vehicle:
02 WRX
15 WRX/05 GTO

Default

It does, there is a microswitch that is activated when the mode dial is moved to the defrost position and turns on the compressor. The light in the AC switch won't come on unless you push the button but the compressor still runs in defrost mode. If you do the mod in the linked thread the compressor will be fully independent and only controlled by the button.
Mulder is offline   Reply With Quote
Old 08-29-2002, 12:23 AM   #5
Chunky_Chicken
Scooby Specialist
 
Member#: 9782
Join Date: Aug 2001
Location: Toronto, Ontario Canada
Vehicle:
2002 E46 M3
Laguna Seca Blue

Default

The AC comes on for a reason, defeating it will dramatically reduce your defroster's effectiveness.

Your window fogs when there is enough moisture inside the car to cause condensation on your colder window. Its called the Dew point.

Your defroster needs 2 things to work properly. It needs to be drawing air from the outside (not recirculating the moist stagnant air from the inside) and it needs the AC on. By running the incoming air through the super cold evaporator you're causing the moisture which would have condenced on your windscreen to condence earlier on the evaporator coils. Thats why you see AC systems dripping water under the car on hot days.

Turning the AC off is gonna let this moisture make it to your windshield, where its gonna inhibit your view.

-Pete
Chunky_Chicken is offline   Reply With Quote
Old 08-29-2002, 07:53 AM   #6
Mulder
Trust no one
Moderator
 
Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
Vehicle:
02 WRX
15 WRX/05 GTO

Default

You're right Chunky, the idea of the mod is not to defeat this function totally but to allow driver control of when the compressor comes on. There are some conditions when just blowing air through the defroster vents will clear the window, and for those times running the AC is a waste. When it's needed the AC can still be used for defrost by pushing the switch. Many cars come from the factory this way so you have the choice of whether to use the defrost mode w/ or w/o AC.
Mulder is offline   Reply With Quote
Old 08-29-2002, 08:28 AM   #7
Snowphun
NASIOC Supporter
 
Member#: 1800
Join Date: Jul 2000
Chapter/Region: NESIC
Location: Way South Shore MA
Vehicle:
WRX /WRX/Cooper S
awd/awd/fwd

Default

Exactly, I'm smart enough to determine if I want the AC on or not. Lots of other cars allow you to make this choice on your own.
Snowphun is offline   Reply With Quote
Old 08-29-2002, 09:11 AM   #8
WRXVT
Scooby Specialist
 
Member#: 17979
Join Date: Apr 2002
Chapter/Region: MAIC
Location: NOVA
Vehicle:
335i Blue

Default

Hey, does the A/C kick on when you have it on the defog/floor setting? I am talking about the second to last setting on the vent controller thing, I know it kicks on when its on the last setting (defrost) but was curious about the other defrost/floor setting.

Also, does anyone know if the a/c sucks less power when the fan setting is low? Like if the fan is on 1, is the a/c running less hard than if the fan is on 3 or 4?
WRXVT is offline   Reply With Quote
Old 08-29-2002, 11:54 AM   #9
FutureWagon
Scooby Newbie
 
Member#: 21924
Join Date: Jul 2002
Location: St. Louis, MO
Default

Quote:
Originally posted by WRXVT
Also, does anyone know if the a/c sucks less power when the fan setting is low? Like if the fan is on 1, is the a/c running less hard than if the fan is on 3 or 4?
No, the fan setting has no DIRECT bearing on how HARD the a/c runs, it IS directly related to how OFTEN the a/c compressor clutch turns on/off (based on my limited knowledge of the way a/c systems work). Since the a/c belt is always spinning when the engine is turned on, there is an electrical clutch on the compressor. When you turn the a/c on, the clutch engages, compressing the refrigerant.

The compressor pumps the refrigerant; the refrigerant goes to the condenser (radiator-looking thing next to the engine coolant radiator) to SLIGHTLY cool off the hot compressed refrigerant; then to a heat exchanger in the dash; the pressure drop in the heat exchanger (evaporator?) causes the refrigerant to get REALLY cold; the climate control fan blows air over the heat (actually cold) exchanger; cold air comes out vents; refrigerant goes back to compressor. There's a thermometer in the heat exchanger, so the more you warm up the cold part in the dash by blowing air over it, the more often the compressor clutch is engaged, using available HP from the crank.

...I think...
FutureWagon is offline   Reply With Quote
Old 09-26-2002, 05:00 PM   #10
whiterabbit
Scooby Specialist
 
Member#: 16755
Join Date: Mar 2002
Location: yo mama's house
Default

i cant find the purple wires to cut. pics? description?

thanks

here is the coressponding thread with how to...
http://forums.nasioc.com/forums/show...hreadid=148118
whiterabbit is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
West Nile is preventing me from working on my car... Kostamojen Off-Topic 10 08-12-2005 04:32 AM
HELP: HID only comes on when on high beam? datdudedennis Electrical & Lighting 1 04-12-2004 12:52 AM
brake light comes on when cornering hard dvs General Community 7 12-18-2002 11:14 PM
E-Brake light coming on when regular braking? Dolphin Overton Brakes, Steering & Suspension 5 12-10-2002 12:56 PM
brake light comes on when shifting hard. dub976 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 4 01-31-2002 06:32 PM


All times are GMT -4. The time now is 09:20 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2015 Axivo Inc.
Copyright ©1999 - 2015, North American Subaru Impreza Owners Club, Inc.