How can I disable the A/C compressor during winter?

jeffleav

My 2000 SE has 26,000 miles and is under warranty. I'm not anxious to make any modifications before the warranty expires in June '03 but the lack of flexibility in the manual climate control is unacceptable. According to the factory manual and Haynes, the A/C compressor is only supposed to run when outdoor air temperature is above 50F. Wrong! The compressor runs on every setting except the 11 O'clock position where air enters the passenger compartment via the dashboard diffuser ports. My '93 Taurus had the same problem. My '91 Explorer has a simple compressor on/off factory pushbutton that works great! In my opinion, Taurus engineering does not seem to be getting the message that the A/C on/off should be a user option unrelated to outdoor air temperature or air flow selection mode.

So here's my proposed solution: I've looked over the schematics and think I can install a toggle switch in the compressor clutch circuit to manually select when the compressor runs. I'd probably hide the switch in an easy to reach location below the dash for rapid winter defog or normal summer operation. Question is: Will interrupting compressor clutch power cause any harmful side effects?

zueslewis

Running the compressor with electricity won't cause any serious effects, but you have to ask - what problem is this, really? Is it worth possibly causing a wiring short and losing major components?

badgerfan

Your AC should only run when it is either on the two AC settings or when it is on the Defrost only setting or the mix of defrost and heat to the lower vents. It does not run when on the other settings. I believe it should shut off when in defrost mode when outside air gets cold, but I do not know if this is true.

If it is running when you have other settings maybe there is a problem. The four settings mentioned above are proper, as you want to dehumidify any defrost air and then reheat it to dry this air so the moisture does not condense on the windshield under certain high humidity situations. I have never found the factory setup to really be a problem, and have been driving Tauri in the Snowbelt-all kinds of different climates-since 1990.

kinley

andre1969

...when you run the defroster in your car, that runs the compressor, doesn't it? Would that be enough to lube all the seals, or should you still put the a/c on for a bit, too?

haspelbein

I know exactly what control jeffleav is talking about, because I have the same issue in my Ford Ranger. Ford decided to save the space/money for an extra A/C switch. So, unless you're using the dashboard vents (11 o'clock position), the compressor will run.

It makes sense for the defroster, as it minimizes window fogging during rainy winter days. I never quite understood why the compressor is on for the footwell vents. (Maybe drying the feet will reduce athlete's foot ?)

Anyhow, I wouldn't disable the A/C compressor, because you'll never know when you may simply want to use it to remove moisture from the cabin air.

swschrad

what's needed is to build a head in the a/c system so oil circulates with the refrigerant, and thus reaches all the seals in the system. as a bonus, in the misty foggy range of weather, it sucks excess humidity out of the passenger compartment in defrost mode.

0patience

Question is: Will interrupting compressor clutch power cause any harmful side effects?
Most definitely will.
Kinley hit it right on the head.
The compressor needs the oil to keep it from seizing.
Your A/C compressor will run (as was stated) in defrost, that way, the A/C system still runs and the A/C system also helps to dry out the vehicle (as was stated).
The A/C switch on the Rangers is for A/C max. It should still come on with the defrost. At least the 02 Rangers we have at work do.

If you disable the A/C for any length of time, there is a chance that by the time you go to use it again, there may be a problem with it.

rogertc1

hi

0patience

Let me rephrase my answer.
The compressor needs the oil circulating to keep it from seizing.

swschrad

regardless of whether a user has or has not in the past had good luck with taking the compressor out of service in the winter, it has never been a recommended practice AFAIK, and in fact the opposite, let it run in the intended modes, is the designers' plan all year round.

I suspect that this recurs on the basis of somebody saying it will save you gas, save the whales, whatever. it's a trade-off along the lines of putting the widest tires availiable on the option list on your car.

ain't worth fooling with.

mullins87

you should run the compressor for at least 15 minutes a week regardless of the weather. I don't know if that's true, I'm no engineer or certified mechanic. I can tell you in my younger days when I preferred having the windows down and radio up that I lost three compressors to lack of lubrication.

swschrad

and there's little reason to think the minimum run times are any less. nothing significant has changed in the mechanics. the refrigerant and oil are different, but 134a is supposed to be a close enough operating twin to the old refrigerant to expect major difference.

rogertc1

When I put some of my cars away for 6 to 7 months at a time I don't start them. (I have summer cars and winter cars.) My 1982 Lincon TC's A/C died this last sumer with 110,000 miles. Would freeze one out of the car until it gave it up the ghost. It lasted 20 years. I would not drive it in the winter and perhaps use the AC a month or less in the summer. Perhaps if I ran it 15 min every week it would still be alive..I don't think so.

kinley

0patience

What ever you say, the o-rings for R-134 are a little more finicky when it comes to things like moisture, drying out and leaks then R-12 used to be. Even at that, R-12 leaked over time.
The system is designed to be run to lubricate it.
Why not use it as it was designed? Maybe keep it from going belly up. I have seen vehicles with 300,000 miles on them, with the original AC system, even after a replacement long block went into it.
Do what ever you want. That is up to you, but the person asked if it could harm the system, Yes.
Moisture can contaminate the system, just from sitting. Just like brake fluid can absorb moisture.
You ever flush the brake fluid system on your vehicles? Didn't think so.

tboner

I've dropped probably a grand into the A/C in 30 months.

New compressor clutch
New dryer and pipe repair and R134 conversion
Replace hose that broke a year later after repair (broke in different spot)

Ok, maybe more like $800-900, but pricey to keep the cooling.

And my grandmother had the compressor replaced when she owned the car.

FWIW,

TB

brucelinc

In reading these posts, there does not seem to be a consensus on when the compressor should run. I can't imagine there being differences based on where the car is built or sold but here is how my Ford products operate:

Badgerfan is right. The compressor should run in the A/C mode, the defrost mode, or the Defrost/floor (mix) mode. It does not run in the vent or floor mode.

Even on older Explorers or Rangers that had the button to activate the A/C would automatically turn on the compressor in the defrost mode if the outside temperature was above a certain level.

Jeffleav and Haspelbein, if the compressor is running in the floor mode on Taurus or Ranger, I think you have an electrical gremlin.

zueslewis

everyone else seems to be guessing, me included. he's the only hard-core certified guy I've seen in this topic.

brucelinc

I agree 100%. I am perfectly happy with the operation in defrost or mix for all of the reasons already stated. My point, however, is that the compressor does NOT run in the "floor" mode on a 2000 Taurus. It seemed that some were saying that it did.

0patience

To be honest, the A/C link in my profile are the A/C pros. They make me look stupid when it comes to the A/C stuff.

brucelinc,
I am pretty certain that in floor and vent, your A/C compressor isn't running. I would have to double check that, but it is pretty much a standard.

brucelinc

Checking the owners manuals of my '01 Taurus, '01 Ranger, and '00 Lincoln, all say the same thing. The compressor will not run in the floor or vent modes and will not run in the defrost modes if the temperature is under 43 degrees. I have had other Taurus, Rangers, and T'Birds since the mid '80s and all have been the same way.

Today, I experimented with my Ranger. It is about 25 degrees here in Minneapolis and the only way I could get the compressor to run was in "max A/C" mode. It would not run anywhere else as long as the truck was outside. After I parked it in the garage (about 55 degrees) for an hour or so, the compressor would run on the defrost or defrost/floor mix mode but not run in the floor or vent positions.

This seems like very logical operation. Why would anyone want to change it?

pjyoung

I run my AC a few minutes per week, regardless of the weather - even if I have to put it in manual mode to do it. Why the concern over the compressor running in the winter - it's not robbing you of any significant power is it?

swschrad

air conditioning takes from 10 to 15 horsepower to operate, potentially 20 HP on a big system like a suburban or a limo. it will drop you a minimum of a half mile per gallon in all probablility.

for a weekly 5 or 10 minute run, it would be like idling 7 or 15 minutes with the a/c off, maybe.

there's a hit, but less than the cost of manufacturing replacement parts, installing them, recycling the offal, as well as the impact of the lost refrigerant on the environment... if you go the green route and total up all the costs of the transaction.

looks to me like the best thing to do is run it.

rogertc1

I would not. Please tell me of a car the the AC has run without repairs as you state for 300000 miles? Was the car 25-30 years old or was it driven that milage in 2 years??

alcan

Mine's getting there. 1993 Taurus SHO, 325,000 kms (about 202,000 miles). I serviced it for the original owner before buying it from her so I know the repair history. AC system's never been opened up and blows 38-40F from the centre vent on Max @ 90F ambient. The only AC repair was a new blower fan speed control module about a year ago.

0patience

I said original A/C system. I didn't say that it never had any repairs, although a few of those vehicles never had anything done to them.
These are fleet vehicles. They see a regular maintenance routine. As for the age of them, years range from 84-95. Some have more than the 300,000 miles on them. Like I said, they are fleet vehicles.