Kill the AC with Defrost on?

[dvdswan]

So curiosity has got me. I'm wondering if you can keep the AC compressor from kicking on when you are in defrost modes? I understand the conditioned air will clear up a foggy windshield faster but it's not always necessary.

So is there a way to do this?

 

[Curious Hound]

You could add a switch in series with the compressor clutch.

 

[RonD]

Yes, the AC evaporator Dries the incoming air so when the Defrost vent blows it on the window the drier air sucks up the moisture/fog much faster

Yes, the only way to defeat this would be to add a manual switch in the cab that disabled AC start up
The year of the Ranger would decide where it would be best to prevent start up

In a 1991 if you just want it off for the winter unplug the AC compressor clutch wires

Or run a new ground wire for Clutch into the cab and use a switch to ground it in the cab or not
So just 1 wire needed


Other thing to think about is "disuse" and lubrication, I would let the compressor run at least once a month to keep bearings and seals in the system lubed
Anyone who has bought a "low mile" vehicle knows about how bearings and seals can dry out from disuse, lol

 

[kunar]

Assuming we're talking about the 91 in your signature, I'd think it would be pretty easy. Something's gotta tell the a/c to come on when it's in defrost mode, so there's gotta be a switch somewhere you could intercept. In this pic i stole from ebay, it appears theres a microswitch that would be depressed when the lever is all the way to the left in the pic (or the right from the rivers seat.) I really believe it would be as simple as putting another switch (a toggle, or maybe a push-on-push-off) in line with one of the wires coming off of that microswitch. Would be simple to put it in the dashboard where you can reach it easily.

Edit: I haven't done this, it's just an educated guess. Do your research before you start chopping wires.

2nd edit: I just realized this was in the explorer section so you're probably talking about your 2002. Probably still old enough to be similar, might start out by looking through an EVTM.

 

[RonD]

Yes, if you want to pull out the Climate control panel there are 2 jumper wires, for Defrost AC control
Yellow wire or light green/purple stripe wire

Disconnecting either would disable AC start up in Defrost mode
You could of course added a switch to reconnect the cut wire

Diagram for 1991 seen here, AC 1 has climate control

 

[Curious Hound]

Just keep the throttle wide open and that will stop the AC.

 

[dvdswan]

I was actually thinking on the 02 Explorer. I would still use the defroster with AC when needed, I just don't need the AC on all the time.

I didn't know the 91 was the same way, that is a bummer, I love the choices that JDM vehicles have the option of AC on/off in any mode and fresh/recirc air flow in any mode.

And thank you for the replies.

 

[Angie]

1 other option is to buy a non AC belt and bypass the whole thing from engaging... ??

 

[wildbill23c]

You can unplug the AC compressor clutch that'll stop it from coming on, however if you are thinking its going to save you tons of gas it won't. It'll cost you more money in the long run from the AC compressor not operating creating lubrication issues for the compressor. In newer vehicles it may even throw a code telling you your AC isn't working LOL.

 

[dvdswan]

I guess you guys are missing the point. I don't need the AC compressor on every time it is in the defrost mode. Yes it is necessary some times but not all the time. The AC compressor will get used probably 40-50% of the time. That is why I want to by pass it in the defrost mode but still be able to turn it on with the AC button. So still have a functional AC system.

I hope this clears up the confusion.

From the PDFs @RonD posted for the 91 Ranger...

I could break the defrost ckt 303 (yellow wire) or ckt 348 (Light Green/Purple wire) at C215 and still keep the AC system working. I just don't know exactly where C215 is or if it is part of C214.

I'm looking for the same thing for the 02 Explorer with the 4.0L.

 

[RonD]

C214 and C215 are on the back of the climate control panel

 

[dvdswan]

C214 and C215 are on the back of the climate control panel

I was hoping for that. I haven't pulled the climate control yet but imagined it would be pretty simple. Thanks @RonD

 

[RonD]

If you add a switch to either C215 wire it would only disable AC in Defrost mode, turning on AC manually would still work, even in defrost mode

Or just cut either wire, tape the ends, and you would just have manual AC on, no "automatic AC on" in Defrost mode

 

[franklin2]

I guess you guys are missing the point. I don't need the AC compressor on every time it is in the defrost mode. Yes it is necessary some times but not all the time. The AC compressor will get used probably 40-50% of the time. That is why I want to by pass it in the defrost mode but still be able to turn it on with the AC button. So still have a functional AC system.

I hope this clears up the confusion.

From the PDFs @RonD posted for the 91 Ranger...

View attachment 67072

I could break the defrost ckt 303 (yellow wire) or ckt 348 (Light Green/Purple wire) at C215 and still keep the AC system working. I just don't know exactly where C215 is or if it is part of C214.

I'm looking for the same thing for the 02 Explorer with the 4.0L.

I still don't get the point. Do you think you are saving fuel?

 

[dvdswan]

Wear and tear. I rarely use the AC system. It does save on gas. On average in the Expo I get about 19.5 with the AC/Defrost off, having it on I get 16 and that's having the defrost on only half the time so it will be less having defrost on all the time.