A/C on Defrost

Can anyone assist in how to disable the A/C compressor when using the defroster in an '03 PreRunner?

Thanks Glenn

to reply directly, remove the ZSPAM from my email address.

Reply to
GH
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Why would you want to do that?

Reply to
slug bug

Why? That is what it is supposed to do. It is much more efficient with the A/C on to blow dry air in the windshield.

G-Man

Reply to
Gary F.

Because some people like to run in 'defrost' vent position when true 'defrost' isn't needed!

On Sat, 20 Dec 2003 16:47:54 GMT, "slug bug" found these unused words floating about:

Reply to
J. A. Mc.

Some of us like to just have plain air coming through the front windscreen vents instead of blowing in our faces from the dashboard! Some of us don't need actual 'defrosting'.

Other manufacturers have learned that people can push a button --- all except "Big-T"!

It would also have been nice it "Big-T" had decided to NOTIFY people of this 'feature' in their joke of a 'manual'. Not ONE word in mine !!!

Wondered why the milage was so low until I found out it was always running the A/C. Now I HAVE to take it off the windscreen vents OR suffer crappy milage. (Good engine though, didn't really notice the A/C was 'on'. )

Gary ... Ever hear of Personal Choice?

GH ... It 'theoretically' should be possible to 'reprogram' the "panel vent computer" - so "Big-T" and a tech on this group have said, but the "Big-T" regional rep. (supposedly sent from dealer - though that could be a joke too!) NEVER got back to me about actually doing it! I'm now looking at just putting an A/C "kill switch" in line with the compressor ... PITA!

On Sat, 20 Dec 2003 12:54:48 -0500, "Gary F." found these unused words floating about:

Reply to
J. A. Mc.

Its a push button option on my '85 4Runner. I guess automating the feature is a sign of progress.

Reply to
Roger Brown

For the same reason I deleted it on my Tacoma. I couldnt swap it to the floor or vents without feeling like I was in a sauna. See, once all the moisture is trapped into the evaporater core, turning it to vent turns the AC off and it all turns to steam. Now sure, I could turn AC on manually, but when the air is dry enough, I dont need the dehumidifier. So for now, just unplug that 4 pin connector in the high side plumbing. This will turn the AC off. Plug it back in in the summer. I removed the connector at the microswitch. Newer rigs, its all done via an electronic system and cant be delted without disabling like I explained above.

Reply to
MDT Tech®

Whoa, this only showed up in about 1996 on Toyotas, and all by 2000. GM< Ford have been doing this on their rigs way back. GM started even earlier in the late 70's

Reply to
MDT Tech®

This is true. Our 1985 Cressida had a button for turning the a/c on or off. My 1988 4Runner has a separate button for turning the a/c on and off.

I can't believe Toyota stopped doing this as it makes sense from a usability perspective.

We had a 1969 Bonneville and, yes, it 'automatically' switched the a/c on when you went to defrost or anything else for that matter. It had the old norm/vent sliding switch. And, when you moved the main switch, this one always flipped back over to 'norm' which meant the a/c was going to run. My dad eventually figured this out (95% of drivers probably didn't) and made it a habit to always flip the switch back to 'vent' which left the other five family members wretching most of the time. I guess if we had our way, we would have voted to take away his 'freedom of personal choice' and taken our chances with the a/c running pretty much all the time. Just call me a pinko, jamc. :^)

All in all, giving the user the option to switch the compressor off from the cockpit at any time makes perfect sense. I am surprised Toyota has changed their position on this. It would be interesting to know what their engineers were thinking.

Luther

Reply to
Luther

On Sun, 21 Dec 2003 02:18:19 GMT, MDT Tech® found these unused words floating about:

Whoa, too!

NOT on my Mercury (91 - pass) or Chevy (96 - 1/2 T).

Reply to
J. A. Mc.

On Sun, 21 Dec 2003 02:16:49 GMT, MDT Tech® found these unused words floating about:

Any idea which single wire in the 4 pin connector would do that - then I can rig a switch?

75% of the time crawling in the desert you don't want the A/C, but it's better to have the windscreen vents blowing air (plain air!) when going or returning, then the A/C might be nice ... .
Reply to
J. A. Mc.

The idea is a good one, to remove moisture. But it also has a negative side affect. I'm old school, I'm fully aware of hot to use the AC as a dehumidifier and when I really need to remove moisture, I'll just push the button. And as for removing ice on the outside of windsheild, the dry air doesnt help one iota.

Reply to
MDT Tech®

Are you sure? I'd check again. If either of these cars have AC, it will run in defrost. I know the Chevy will for sure. As for the Merc, I've seen this show up in late 80's to early 90's on some Fords, all by now. Double check! ;-)

Reply to
MDT Tech®

Give me a year and model, I'll let you know.

Reply to
MDT Tech®

On Sun, 21 Dec 2003 17:02:12 GMT, MDT Tech® found these unused words floating about:

I have - the A/C clutch isn't engaged!

Started the C, Ice Cold (well for here anyway ), Defrost ON ... No A/C clutch engaged.

Could be because they're both DESERT bought?

Maybe they're smart enough that "One size doesN'T fit all?

Reply to
J. A. Mc.

On Sun, 21 Dec 2003 17:03:10 GMT, MDT Tech® found these unused words floating about:

Tacoma DC, 2002

I'd asked about this in posts after I bought it. You were the one that clued me into the A/C always being ON and PP milage. IIRC ... also indicated that you might be able to find a 'reprogram' for the computer.

Reply to
J. A. Mc.

Yes, there is a way to do it on some models, downfall, if the battery is disconnected, its all back to default, nanny AC. As for the wiring in a switch, cut the black wire with a blue stripe. This is available at the AC control unit inside the truck also. Its on pin #3. Would be close ot the AC evaporater core behind the glovebox.

Reply to
MDT Tech®

On Sun, 21 Dec 2003 21:45:11 GMT, MDT Tech® found these unused words floating about:

Thank you!

Reply to
J. A. Mc.

One of the functions of this feature is to prevent the lockup of the compressor from non-use in the winter months. I'm all for manual controlability, but just remember to engage it every now and then.

Reply to
A57Redfish

Good comment. Its a good idea to operate it once every couple of months to move some oil around, keeps o-rings and seals moist.

Reply to
MDT Tech®

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