OK so heres what i figure,
I have a 1995 dodge ram 1500 318 and whenever i turn the **** to defrost the air conditioning comes on to clear the windshield, I know this because I can hear the compressor when stopped and there is cold air coming out of the vents near the windshield even when its on hot. So i was wondering if there is a way just to have air wether it be warm or cold air blow against the windshield for gas mileage and because in the winter i could just have hot air blowing against it. Any ideas thanks

 

It's supposed to be a deFOGGER, too. The dried air coming off the evaporator is what eliminates the fog on the windshield. I hate the set-up too because on the wife's Toyota, you can use outside air/no AC and it defogs just fine. Only when it's set to recirculate does it fog up ... BAD! Apparently, the defrost setting uses recirculate/AC on.

You can't just turn the heat to MAX and get it hot? Mine gets WAY hot ... after a good warm up.

 

no i cant if i have it on head/feet with the warm then switch to defrog it turn on the a/c and blows cold, my friend had the same thing in his civic the a/c would come on but by turning th ekey and pushing some buttons in sequence he reprogrammed it to where he could turn it off

 

If you have no heat, I would say a t-stat problem, low coolant, plugged core, etc.

I am pretty sure the compressor only cycles for a few seconds every minute. I thought it was every 45 seconds in the defrost mode, floor mode, and bi level modes.

I think the truck uses the evaporator to cool and dry the air. If the humidity is not removed, I don't think the winshield would "defog".


What's your eng temp gauge say?


Good luck.

 

it's just below 95 but i put in a 180 thermo it just that i just want air to blow against the windshield not a/c air

 

Just below 195 or 95? There is quite a difference there lol. If it truly is at 95 you have a problem. You should have a CEL for the engine running too cold and I would look the thermostat being stuck open. If its at 195 and the A/C is kicking on when you turn on the defroster then everything is operating like it should. As far as turning off the compressor when the defroster is on, I don't know. I would think that the computer controls that function and it would have to be reprogrammed or you might try unplugging the pressure switch for the A/C compressor. I don't think it is going to save you that much on gas in the long run though.

 

oh yeah srry forgot to mention it's in metric so its a good bit below 95 whatever that is in imperial ya i don't think it would save much glass just be better if i could have some warm air blowing against my face just wondering if there was an easy fix for it or not thanks anyways

 

LOL ok, I have to say I was a little more than worried when you said 95, I was thinking "how is that even possible". Anyway you could try unhookin the A/C pressure switch just don't forget to hook it back up when it gets hot outside and you need your A/C, it shouldn't hurt anything.