PDA

View Full Version : Shutting down A/C while in defrost mode!



COSi
12-23-2002, 09:29 AM
Not completely sure if anyone else has discovered, or posted this here yet, but I found a solution for those of us who DO NOT want our A/C unit to be on during defrost mode.

1: Car must be turned off
2: Turn both the A/C/Heat control and Fan control all the way counter clock-wise (this would put them at the coldest and the off setting)
3: Press and hold the A/C AND the re-circulation buttons (remember, you must be HOLDING THESE DOWN)
4: Start your car and wait about 7 seconds or so for the re-circ light to flash and then your A/C light to stay on. At this time, you can release the buttons and enjoy "A/C-less" defrosting modes.

NOTE: Car will still by default turn on A/C when either defrost modes are selected, but can now be turned off!
:D

CivicSiR4U2NV
12-23-2002, 04:15 PM
been there done that moving on............


and the a/c compresspor is not running when the light is on it...it just passes the air through the condensor.

Jpax
12-23-2002, 07:54 PM
Originally posted by COSi
Not completely sure if anyone else has discovered, or posted this here yet, but I found a solution for those of us who DO NOT want our A/C unit to be on during defrost mode.

1: Car must be turned off
2: Turn both the A/C/Heat control and Fan control all the way counter clock-wise (this would put them at the coldest and the off setting)
3: Press and hold the A/C AND the re-circulation buttons (remember, you must be HOLDING THESE DOWN)
4: Start your car and wait about 7 seconds or so for the re-circ light to flash and then your A/C light to stay on. At this time, you can release the buttons and enjoy "A/C-less" defrosting modes.

NOTE: Car will still by default turn on A/C when either defrost modes are selected, but can now be turned off!
:D



WOW



http://members.lycos.co.uk/paxie/newpage2.html

COSi
12-24-2002, 08:29 AM
Hey, I never claimed to take credit for this, I was just trying to share it. I said I "found" a way, not discovered. Anyway, Paxie, nice website sorry to post already done material.:confused:

BarracksSi
12-24-2002, 10:20 AM
I was happy to learn of this, too. But, I need to remind myself to run the A/C once in a while to keep the system lubed & fresh.

COSi, drop me a line -- I drove my EP to Omaha to hang out with the family for the holidays. It's certainly alright for an airman to hang out with a Marine, right?

aman
12-28-2002, 03:13 PM
Is it possible to switch it back to the original way? That is, AC automatically on when defrosting.

PoRT
12-28-2002, 03:20 PM
i did all that like 50 times and it dont work for me, lol

taikahn
12-28-2002, 08:35 PM
Originally posted by PoRT
i did all that like 50 times and it dont work for me, lol

me too


wtf?

BarracksSi
12-28-2002, 08:57 PM
Worked for me. Stated again:

Turn off the car completely.
Turn all the climate control knobs all the way to the left.
Insert the key, and turn it to the Accessory position (only the radio comes on).
Press and hold BOTH the A/C and the Recirculate buttons.
Turn the key to the On position (no need to start the car, but the dash warning lights should come on).
CONTINUE to hold the A/C and Recirculate buttons until the Recirculate button blinks and the A/C stays on.

Now, the A/C will come on automatically when you switch the vent knob (the top one) from Face or Feet to either of the two modes involving Defrost. BUT, you can now switch the A/C off once you are in either Defrost mode.

The A/C button does run the compressor, however. The owner's manual states that the A/C should be turned on from time to time (recommends ten minutes per week) so that it can remain lubricated and fresh.

The condenser is worthless without an active compressor, and the whole point of using A/C with defrost is to blow warm, DRY air across the windows, making the defrost/defog process much, much more effective. Choosing to turn off the A/C system enables normal gas mileage and more power to the wheels when the "full power" heat + A/C defrosting approach isn't entirely necessary.

CivicSiR4U2NV
12-28-2002, 09:22 PM
Originally posted by BarracksSi
The A/C button does run the compressor, however. The owner's manual states that the A/C should be turned on from time to time (recommends ten minutes per week) so that it can remain lubricated and fresh.

Listen I asked 3 of the technicians at my dealership about this and they all told me that when the defrostor is on the a/c compressor does NOT run. Are you telling me the the technicians don't know what they are talking about.

http://www.torontocivics.com/tccforums/images/smilies/slap.gif

Jpax
12-29-2002, 03:14 AM
Originally posted by CivicSiR4U2NV


Listen I asked 3 of the technicians at my dealership about this and they all told me that when the defrostor is on the a/c compressor does NOT run. Are you telling me the the technicians don't know what they are talking about.

http://www.torontocivics.com/tccforums/images/smilies/slap.gif

Uhh were telling you that when you do this SIMPLE push button mod, the compressor TURNS OFF WHEN YOU WANT TO.

Factory when you start the car and turn the dial to windshield blow air, it turns on the commpressor ON. when you do the mod you have the choice to turn it on or OFF. ....


Ill do a video of that as well tomarrow. :mad:

SubliminalSi
12-29-2002, 01:17 PM
Worked for me:)

CivicSiR4U2NV
12-29-2002, 02:19 PM
Paxie forgive me plz ;)

I am only going by what the techs told me and if that info is wrong I'll go set them straight tomorrow.

jo3y
01-02-2003, 08:42 PM
cool - i thought i was screwed everytime i wanted defrost but i just did this and it works! just the simple mod i wanted

SpUD
01-02-2003, 09:34 PM
It works for me...... took 10secs. Thanks... i always wanted to get rid of the a/c while in defrost.

BTW.... how do i switch it back? just want to know....

Jpax
01-02-2003, 10:55 PM
Originally posted by SpUD
It works for me...... took 10secs. Thanks... i always wanted to get rid of the a/c while in defrost.

BTW.... how do i switch it back? just want to know....

Turn the knobs the opposite direction, and do it the same. :eek: :cool:

Cousin Avi
01-09-2003, 05:59 PM
This is great. I'm so glad I can have the choice again! Right...one question...Is this mod a specific function put in by Honda? or is it just a conveniant 'bug' someone found?

DwooLEY
01-09-2003, 06:15 PM
Honda Put this there for extremely cold environments. It's part of the dealer prep process in places where there are temp extremes most of the year.


and by the way, when the A/C button is on, no matter what the position of mode ( defrost, vent etc.) the compressor constantly cycles on and off. so you're all right, sort of. when it's in defrost tho, it actually runs MORE, because the action of the A/C system when the compressor is working removes moisture from air. look under your car on a hot day with a/c on, see the puddle?
just running the air through the system will not remove moisture unless the system is on.

sniperSI
01-09-2003, 06:31 PM
i don't know what i did, or if this is how it is supposed to function, after doing that fix and thinking it 'didnt work'


few days later i noticed i could toggle my ac on and off when in defrost mode, is this what it's supposed to do, or just constantly stay off.

either way, way.

BarracksSi
01-09-2003, 09:38 PM
Yup, sniperSI, that's what it's supposed to do.

If you have the vent set to, say, face or feet, you can toggle the A/C just like you did before. When you switch to either of the two modes with defrost, the A/C will come on automatically, just like before -- except that now, after entering the code, you can switch the A/C back off.

If you don't turn the mode dial away from either defrost mode, the A/C will stay on or off the next time you start the car, depending on your earlier choice.

It's still a good idea for the A/C system to run occasionally (at least once a week for ten minutes or so) to prevent corrosion of its internal parts. I believe that's what finally happened to the A/C in my '86 Si, and by that time, replacing the whole system would have cost more than the car was worth.

In extremely cold environments, it's not a good thing to have moisture from the system freezing & blocking its drain, hence the dealer-prepped switchable A/C.

I wonder if there are other "cheat codes" in the car... hehe.. invincibility? All weapons & ammo?

Jpax
01-09-2003, 09:47 PM
Originally posted by BarracksSi


I wonder if there are other "cheat codes" in the car... hehe.. invincibility? All weapons & ammo?

HAHAHa OMG what games you play....... Im a wolfenstein freak and AOE freak too.

sniperSI
01-10-2003, 11:19 AM
Thats what hondata does, all cheat codes!

Ocelaris
01-22-2003, 01:52 AM
I'm waiting for a Goldfinger you hookup to the ECU that turns the K20a3 into a K20a2 :-) Goldfinger anyone? PIII CPus?

ANyways, Just wanted to say that I think this thread should be a sticky. I was about to take my car back to the dealer because I thought the A/C was stuck in the on position... until my mother-in-law commented it was probably on purpose that it comes on in defrost mode... Bill

Jpax
01-22-2003, 02:16 AM
Originally posted by Ocelaris
I was about to take my car back to the dealer because I thought the A/C was stuck in the on position... until my mother-in-law commented it was probably on purpose that it comes on in defrost mode... Bill

Thats why you check out my web-site ;) :D

Ocelaris
01-22-2003, 02:27 AM
I try to limit my bandwidth consumption when it comes to seperate member pages, I know it's expensive when it comes to bandwidth. But your site is an excellent resource.

I would reccomend a donation link on your site. maybe nobody uses it, but I know in a month when I open my car's dash and stereo apart, I'm gonna thank paxie's vids.

I personally would pay at least 10$ for a video of a spring /lowering suspension video... I mean a basic DIY type, not watching a shop do it. But to me the knowledge alone is worth that.

whattda site... Thanks always, Bill

2002Si
01-22-2003, 10:53 AM
My car will not do this, i've tried 300 times and it still won't work

StrangeShadow
02-17-2003, 09:35 PM
I have to defrost every morning.
Which way is faster? and better?
(with a/c compressor on or off?)

Jpax
02-20-2003, 08:10 PM
I would say ON in the pacific north west. but maybe off in the south.

sniperSI
02-21-2003, 03:55 PM
I am not a big AC Guy, here in florida, leave the windows open and i did the defroster thinger to shut off ac.

few months later (now) My vents started to stink. I had to run the AC for a few days to get the smell out but the reasoning for the AC ON when the defroster comes on is true, helps the AC condensor, filter, whatever not to mildew or smell nasty, forget exactley how it was put but it's in a thread somewhere.


So IMO, don't take the ac when your defrosting, not that much gas is wasted and it does serve the purpose honda set for it.

ta2dSi
02-23-2003, 12:47 AM
I was just noticed that when I was driving in the 6 inches of snow on my way home from work, (midnight)

I wsa in defrost, and when the A/C clutch engaged, my head lights got dimmer.

Does everyone else have this problem? I was thinking about taking it to the dealer......


and oh BTW when the cold humid air is made into warm air, the humidity drops.. the a/c clutch is engaged for maintenace purposes, since people normally use the defrost in the winter months, and they is where you get the ten minutes per week from.

I work for one of the big 3 (well now 2) climate control doing wind tunnel testing, for prototypes

Jpax
02-23-2003, 08:54 PM
Originally posted by ta2dSi
and oh BTW when the cold humid air is made into warm air, the humidity drops.. the a/c clutch is engaged for maintenace purposes, since people normally use the defrost in the winter months, and they is where you get the ten minutes per week from.

I work for one of the big 3 (well now 2) climate control doing wind tunnel testing, for prototypes

I don't get it....:o So your saying YOU like the AC on in defrost? and the wind tunels tell you so? are you drunk? because give me a couple and ill understand....but right now im lost :angel:

ta2dSi
02-23-2003, 10:33 PM
I am saying that I am indifferent. I think it is a good thing since people would forget to run thier AC during the winter months. I think that is a good thing since people don't like their AC not working.

But I also understand that performance side of the Clutch engaging. I just noticed that my headlights dim when the clutch engages, and I am now leaning towards the no AC during defrost.

I was also trying to explain why the clutch engages when you are in defrost mode, and the reasoning behind it.

Sorry if I came across like a jerk

I SELL HONDAS
04-11-2003, 08:23 PM
the same thing that makes the a/c work i.e. drying the air will also defog you windows.........dry air = no fog.
whats the mystery?:rolleyes:

BarracksSi
04-11-2003, 10:10 PM
Yup, dry air = no fog. But, also, warm air = no fog, because if the air AND glass are raised above the dew point of the air, then water won't condense and fog up the windows.

So, yes, it's possible to defog the windows without using the A/C. As long as the temperature of the glass is brought above the dew point of the air, it won't fog up.

We all know that the A/C compressor drags on the engine, reducing power and gas mileage. If you need the defroster running on every trip, it's nice -- and economically sound -- to disengage the A/C when the weather allows.

Also, if the outside temperature is really cold, then it's possible that the water collected from the A/C condenser will freeze in the system, causing various problems of its own. That's why, in more arcitc climates, dealers will make the A/C switchable for defogging the windows.

Personally, on some days, the moisture difference between the dried A/C air and humid outside air will start to give me headaches. If I can defog the windows and keep the humidity the same, then that's a good thing.

Marcivi
04-17-2003, 03:46 PM
Myself, I get itchy eyes and my lips dry out when I run the A/C for long periods of time. Could just be that I'm a sissy about things like this. :o

Also, with the car at an idle, I don't mind the A/C on while defrosting, but while driving I like to have it off and only usually turn it on at red lights.

Ocelaris
04-17-2003, 07:12 PM
but while driving I like to have it off and only usually turn it on at red lights.

I'm not sure if it's as big a deal anymore, but from my work with vapor phase cooling systems(i.e. overclocking with a refrigerator), it's not good to turn the air conditioner on and off quickly, you can hurt the compressory by cycling it quickly. I know it took my compressor on my computer >5 minutes before it would even consider turning on again, like it just wouldn't turn over, it took that long for the R-12 to return to equalibrium.

Under normal conditions the air conditioning system regulates the flow of freon into the evaporator, but when you turn it off the liquid which is evaporating can drain backwards into the compressor, and if you turn the AC back on too quickly you'll have liquid in the condensor... i.e. slugging the motor, you can't compress liquid, and it can burn out the motor.

Anyone know the method of controlling the flow of freon into the evaporator (specific to our vehicles)? I haven't done AC in a while, but someone mentioned that the compressor cycles on and off while the "AC light is on". Is that really what's happening? if so what is the time frame that it cycles on and off. I didn't think there were that many variable cycle compressors out there, I know there are a few, but usually that was not the case... so I was wondering about specific mechanisms in our vehicles.

ta2dSi
04-17-2003, 09:24 PM
I think our vehicles are fitted with a TXV system for our air conditioning systems. That is the trend that automakers are going rather than that traditional orifice tube. The TXV is a valve that takes the output from the evap and adjusts a the amount of evaporator superheat under varying evaporator heat load conditions, provided the range and capacity of the valve have not been exceeded. It also keeps the entire evaporator full of liquid/vapor refrigerant under all evap. heat loading conditions for an efficient system, along with preventing liquid floodback of refrigerant to the compressor under varying evap. heat loading conditions.

These are all things that the traditional orifice tube does not do.

When I was driving I noticed that my lights were dimming once about every minute (when the clutch was engaging), but the compressor was only on for about 5-7 seconds.

I hope this helps you out.

Here is a picture of a TXV:http://hvacwebtech.com/TXVMY.jpg

Ocelaris
04-17-2003, 09:58 PM
heh, guess that answers my question, since it definetly was bad before to cycle your ac on and off... with a fixed orifice device, like my refrigeration system with a capillary tube.

So you think our cars only runs the compresser enough to fill the evaporator and then shut it off, 5-6 seconds? I've never heard of something like that I guess? I mean, the AC units in a house I've heard of run constantly until a certain temperature is reached... I read a book on A/C and Refrigeration, or alot of it, but never read about car ac...

Oh, here's another question, how does the temperature gauge work, like does it just change a thermostat? which makes the compressor run more often? Or does the fan system just pick up less of the cold air? I mean, how does the temperature gradient knob work? Thanks, Bill

I actually bought a 1 ton compressor, and 2 ton TXV valve and was going to build my own AC unit, even went to the dump to pickup a discarded evaporator, but I could never find a thrown out condensor, and plus I don't have a good vaccuum pump (they're a hot item on ebay, never found a good deal yet), or welding supplies... ahhh... one day I'll make one ;-) I even bought the R-12 gauges! Wonder if anyone's thought of converting their R-134a system to something better, like propane... I know alot of people in canada were doing that for their old R-12 systems, and I know it's illegal in this great land of USA, and technically not capable I thought because the compressor on an R-134a has a lower compression ratio than R-12 or propane (an excellent refrigerant by the way). Thoughts?