One of the things I like about the '93 Rodeo is when Isuzu built it, they assume ed their customers had brains.

If you want to heat the windshield to do a minor defog or melt ice, you switch to heat and windshield. Do not press the A/C (compressor) button.

The temp in Tucson was such that I turned the 2004 Rodeo to combo defog/foot heat. The Rodeo kept kicking forward at a stoplight. I did not have the A/C (compressor) button in.

A few minutes and holding the brakes very lightly let me verify that when the dial is on Windshield or Windshield/Feet, then the A/C automatically turns on, no matter what the A/C button says.

I blame the idiots who sued, the jury that awarded the price, and the general stupidity of the population as a whole who did not bother educating themselves as to how their expensive vehicle worked. "I just put gas in, right?"

When my Amigo was overheating, I'd switch it to dash, heat, high fan to blow off heat, but not in my direction. No more doing that. With the A/C compressor running, it makes the engine hot and I don't know the net effect.

When I want to heat up the window, I have the compressor fighting the heater. Great.

When I just wanted very gentle, indirect heat, I can still do it--but have to waste the excess gasoline to blow the defroster.

I know, minor complaint. But if you have a specific button just for the compressor, use it. Or light it up whenever the compressor is on. Trust people to be a little smarter. OK, so a guy died Monday because he was hanging his butt outside the subway car to relieve himself on the tracks and the oncoming subway train hit him, but still.

I thought the AC only kicked on with defrost when the outside temperature was above a certain point? It kicks on all the time the defrost is on? Yeah, I hate that feature too.

My wife's Grand Caravan has this feature. I believe the intent behind it is to use the A/C compressor to dehumidify the air inside the cabin, thus reducing fog more quickly on the inside of the glass. I know I've used that trick in my '94 Rodeo, and it makes a huge difference. Of course, Ohio is a somewhat more humid area than Arizona overall.

James

Since the inside fog is more likely at cold temperatures, (condensation working when it's cold outside), if anything it should kick on at lower temps.....but then it's still reducing the temperature of the air.

As far as I can tell, from 80+ degrees in Tucson to below freezing (frost on the car) this morning in Dallas, it always kicks on. No temperature sensor.

I blame the jury that approved the lawsuit by the idiot that sued. Just a hunch.

If I can't have control, I do wish the A/C light would at least light up so you know. Instead you have to guess.

I've changed my heating habits, no biggie. Just an annoyance.

A/C not only cools, but also drys the air. When you have the defrost on in the winter, you usually have the temp knob on warm and it blows warm air regardless of whether the A/C is engaged. But that warm air is dry, thanks to the A/C, and lets the defrost work more efficiently. Blowing humid air doesn't work as well when attempting to defrost, even if it's warm.

Also, there is a temp sensor. Here in MN it gets cold enough where the A/C won't kick in. The colder the air is, the less moisture it can hold, so there's no need to dry the air when it's really cold. I'd be willing to bet you won't likely see temperatures cold enough in Tucson where the A/C won't engage.

Frost on the windows in Dallas this morning!

I was driving slow down the farm roads while it warmed up. Late for work, I didn't get a chance to test it.

I understand the intent in moderate, humid climates. When it rains you get
- People breating in the car
- Wet feet ddrying in the car
Thus it's good to run the A/C to dry the air out.

But it gets down in the 30's in Tucson. Prescott and the like, and on top of Mt Lemmon, it's well below freezing. Here in DFW (another 8 month move, got here a couple days ago) it's frosting up the car.

I want to melt ice. Running the A/C at the same time makes the heat a little less hot. And wastes a little gas.

It's really not a big deal, just a surprise. But I would like.
- Give me full manual control. I even understand the difference between fresh and recirculated air!
- If your not, then turn the compressor light on so I at least know.

I do remember a post a while back discussing this and I believe someone may have been able to bypass the A/C. Not sure though.

I agree that manual control would be better. These trucks really act strangely when the A/C is working (lurching, huge idle fluctuations, etc.).

It seems most cars built in the last 10 years have this feature, but Rodeos defrost just sucks, regardless of whether the A/C is on. Even when the A/C doesn't kick in, the defrost is usually no match for the buildup of ice and frost. On cold days I usually have the defrost blasted but it doesn't quite have the output (heat and volume of air) to work nearly as good as my other cars. And I don't know the exact temp where the A/C stops kicking in, but I think it's somewhere below 15 degrees, give or take. I know my A/C won't be engaging this weekend with a high temp of 0.

I just see it as one in a long list of changes in the auto industry that does everything for us and is supposed to make us safer. How many people do you observe everyday driving that cannot walk and chew gum at the same time, let alone steer and work the climate control.
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Are you SURE it's the compressor kicking on/off?

The late model trucks, Troopers and Rodeos that have the 4L30
transmission will do a systems check when sitting idle, in gear.
When the trans does the system check, it will cause the truck
to lurch forward very slightly and yes, it feels just like
the compressor kicking off.

If you stop at a light for 15-20 seconds, you'll feel the lurch.

If it is the compressor kicking on and off, you should feel
it multiple times while sitting idle, in gear.

Interesting. I didn't know that, but I know exactly what you're talking about. I've noticed it with the A/C or defrost on, so I assumed it was the compressor kicking in.

This is not an issue just with Isuzu's. My Mazda 3 does the same thing when you switch it to defrost without the ac light coming on. Someone with allot of time on their hands came up with a cool fix that makes it work like we want it to, compressor only kicks on when you hit the ac button, but it entails tearing down the whole dash and some minor fabricating and would effect my extended factory warranty. If you are willing to tear apart your dash I bet you could install a similar fix.