Chevy 4.3 V6

[Toddppm]

My est. truck is a 02' S10 with the 4.3, when the heat is on and the ac off the ac still cycles on and off constantly. Is this normal? The hoses feeze up just like when the ac is running but the switch is off?????

 

[Treeman14]

I don't know for sure, but it doesn't sound right to me. On all vehicles I have ever owned, when the switch is off, the AC will not cycle on at all.

 

[rahtreelimbs]

I think that on some vehicals the AC comes on in the defrost mode to help cut down on the humidity.

 

[Toddppm]

A couple people on another forum said the same as Rich too, maybe that's it. Guess I should check the manual! Just seemed weird but I thought it might be something like that. It does it constantly clicking on and off , thought something was messed up in the front end at first!

 

[Korn]

If your heater control is on defrost, or a mix of defrost and heat , the ac compressor will come on to try to dry the air. If the compressor runs with the control on heat only, you have a problem.

 

[Menchhofer]

If you are talking about the switch on the compressor switching or clicking on and off all the time, this is an indication the system needs freon and is not charged properly.....

 

[Toddppm]

I'm pretty sure it's with the defroster/heater on because that's what I use most of the time. The compressor is actually engaging and disengaging, makes a loud click when it does it.

 

[DDM]

In defrost, Defrost/Floor Mix All of my Trucks A/c's Cycle itermeditley So in the winter i unplug the connection at the compressor.

 

[StIhL MaGnUm]

All vehicles automaticlly do this to keep the compressor from seizing,alot of the new cars/trucks you won't notice it cause they are alot quiter than they use to be..It comes on/off to keep the freon and the oils circulating...

Later Rob..

 

[woodsjunkie]

I don't have a 4.3 but I do Have a 02 6.0 and mine dose the same thing. I took it to my dealer and they say it's normal (Or what Rob said)

 

[StIhL MaGnUm]

Oh yeah before I started logging I was working at a radiator-A/C shop Fixing all this stuff...


Later Rob..

 

[Bill G]

Stihl Magnum nailed it dead on.

They cycle to lubricate the compressor. The sould you hear is the electric clutch engaging. If you want to avoid costly repairs I would not unhook the connections to the compressor.

Bill

 

[NeTree]

My '91 4.3L Blazer does the same thing. VERY annoying. I just unplugged the compressor clutch leads from the pump. Alternatively, you could install a toggle switch in the dash to do the same thing.

Erik
[email protected]

 

[Jumper]

I would rather put up with the clicking than deal with a $1000 repair bill later because the innards seized after disabling the circuit or whatever. Especially on pre 94 vehicles that use the old freon system you are looking at replacing all the ac components with one compatible with the new equivalent of freon (one is R12 the other R34, can not remember which is which right now) . Quite a few vehicles also have a switch the prevents the complressor from coming on when the outside temp is below 32F/0C as well, I guess to keep the system from icing up, when only heat and a cracked open window will do.

 

[daveb]

You guys are don't know what you're talking about. Rich Hoffman nailed it. The A/C compressor comes on during defrost only to dry out the air in the vehicle. This is normal. It does not come on to keep the compressor from seizing up or any other reason you might imagine.

 

[NeTree]

Yes, he is correct.
But guess what... all it does is make for an unnecessary annoyance. Yet another case of fixing something that wasn't broken.

I simply unplug it in the fall, and plug it back in in the spring. My defroster works just fine without it, and I don't have to hear the AC clutch kicking in every 10 seconds or the computer/ISCS trying to keep the idle speed correct.

 

[Jumper]

I am not a a mechanic, but I have read elsewhere that the system cycles even when not on for a reason. The maker would not have built a glitch such as this into the engine controls without a good reason. As for defog working fine without the benefit of the ac, you must not live in a very moist area. Nothing is worse than a defroster blowing undehumidified moist cold air from a foggy or damp day outside across a cold windshield.

 

[NeTree]

In this particular application, cycling any other time means somethings wrong.

Jumper, since I don't live as far north as you anymore, I can't say I really use the defroster all that much. I just know it works fine here where I am, and it's the only vehicle I own that does it.

As for necessary? That's hard to define nowadays. Do suburbian soccer moms really need an Escalade burning all that fuel just to commute back and forth to Boston? Do ya REALLY have to have power windows? Is it really all that important to be able to unlock your truck 300 feet before you can even get in anyways? And what's so bad about getting off the darn couch to change the channel?

I classify it as more of a convenience to people who are too impatient to let the vehicle warm up a few minutes before taking off.

 

[Jumper]

Letting a vehicle warm up for a few minutes also contributes to poor air quality-in Germany it is illegal to do so for more than one minute! As for the SUVs on the road I agree, and when the price of fuel hits $3.00 a gallon GM, Ford et al will not be able to give them away.

 

[NeTree]

I'm getting off topic, but...

Originally posted by Jumper
As for the SUVs on the road I agree, and when the price of fuel hits $3.00 a gallon GM, Ford et al will not be able to give them away.

Exactly why the Blazer is getting replaced later this year by something more along the lines of a Metro or something. It only gets used for job quotes and small errands (like filling gas cans that ran out, etc.) anyway. Something cheaper initially, and alot better on gas.