I didn't want to hyjack the air conditioning thread so I'm here

I've been asking air conditioning questions for over a year now and it gives rise to a new issue. The air Temp control ****, the one that slides left to right might be at issue with me. Is there a way I can check that when I slide it all the way to the left that I have full cooling? If I move the slider **** 1/8 of an inch to the right, while still in the "blue" cooler section the air gets substantially warmer. I might be having a problem with whatever mechanism opens and closes as you slide that lever from cool to warm. I'm thinking the heater core might not be shut off with the lever all the way to the left?

brad.

 

on my 92 all the way left closes the vac. actuated valve and cuts off the water to heater. breathe on it to the right and water is on. hot air
Clark

 

I have to disagree with you, Clark. (Having had the whole dash and heater box apart recently to do a heater core.)

The slider is connected ONLY to the damper door in the heater box. Coolant circulates through the heater core at all times except when the OFF or MAX buttons are pushed. In the summer that heater core is nice and toasty, so moving the slider just a wee bit bleeds in some nice 200 degree air. Doesn't take much to change the temp dramatically. The cable is self adjusting. I think your system is working normally, Brad.

 

Thanks Dave.

I just thought maybe the heater box door might not be closing then? somedays the air feels nice and chilly and other times not so chilly and I thought there could be a way to check to see the door has shut all the way

brad

 

Yeah, you can pop the cable off and reset it to make sure the damper is closing all the way. Just pull the glovebox out and wiggle the slider a little while you watch to see what moves. You'll figure out how it works in no time.

 

I too have noticed this sudden warming thing but my truck has a vacuum operated valve on heater hose which I think turns off the flow to the core. I just guessed that it opened up flow when the ac-heat controller was turned towards the heater side. My chev had a full time flow to the core and you could tell things were toasty in there all the time. The dodge does not seem to radiate heat in the same way. Now I am not sure how it is set up.

 

It is exactlly like Wanna says. The temp. control uses a push/pull cable that regulates the "blending damper" only. Problems that can arise are:

1. The door isn't closeing all the way, which usually is easily fixed by adjusting the clamp on the cable behind the glove box.

2. There is supposed to be a foam like material gasket, more like weather stripping around the edge of the door to help it seal. After years of hot and cold this material disentergrates allowing some leakage.

3. The vacuum valve leaks by. You can replace it if you can find one or you can put in a manual valve and only open it when you want heat. This can be a pain if you live in a normally hummid climate and run your a/c to dry out the inside of your truck or for defogging the windshield.

 

My Ball water shutoff valve: http://www.turbodieselregister.com/u...d=6710&width=0

 

You guys are right. The vacuum operated shut-off valve does not shut off completely. The sudden apparent drop in cooling when my ac is not on full is likely due to the thermostat opening and closing... I do get the fluctuation in temps cycle effect except when it is really hot. The presure on the valve would greatly increase when the thermostat closes. And then there would be more hot coolant getting into the core. It is cool and rainy today and even though the heater is shut off, there is about equal heat in the supply and return heater hoses. I shall add a shut off valve. I have another question though: When you replace the vacuum controlled valve with the manually operated one, did you get better coolant flow?

 

Mine just flucuates between freeway speed (low and adding heat to keep from trurning into a popsicle) and, in town speeds (on med to hi depending on the temp out side)