max a/c switch

[Fire Marshal Bill]

I was reading the thread about cleaning the evaporator under my dash. I think that may be the cure for my less than impressive upgrade to 134 last year Oo. I bet it has never been cleaned. Won't get any cooler than about 58 degrees. I guess the sound of rustling leaves when i turn the a/c on should have given me my first clue huh .



Anyway, to the question... ..... is there supposed to be a noticeable difference in the force of the air blowing out of the vents when you activate the MAX A/C button. I'm guessing the answer is going to be "yes". I notice absolutely no change in the amount of air blowing out when i depress the button. Is there a remedy for this or do i need to look into replacing the whole control panel? Thanks.



Melting in Texas

 

[ARhine]

no change in air volume really. All max does is the system recirculates inside air. Norm pulls in outside air.

 

[B.G. Smith]

You should hear and feel a change in the air flow when you go to max. air. All that happens is a door switches the inlet air from outside to inside, you should be able to look under the right side of the AC housing under the dash and see if the door is working, might be a bad vac. motor or a loose hose. bg

 

[1stgen4evr]

max AC

As already stated, you will hear and feel a difference but there is no increase of air flow, just a change of circulation. All the air going through the system is recirculating inside the cab. It will definitely make a difference in the overall temp inside when you cut the outside (Texas) air off. I was in Dallas last weekend and I can vouch for the melting temps there. If you have not cleaned the evaporator and it IS clogged, you may see a little bit of increased air flow at highway speed when the system is on AC (as opposed to Max AC) due to the ram effect of the outside air. If you have not looked at the Ramcharger central site do that and you will see your problem.



While there have been a lot of control panels changed, many were not the problem but rather clogging of the evaporator as shown. I changed one years ago before I became a member on TDR. In fact, I did several things that were useless before I tapped into the info here.



Which brings me to a post I have made before. There are still thousands of first genners that don't know about TDR. I make an effort to discuss this with owners at the filling stations where I have a little time. Often as not I get a stand-off-ish response till they realize that I am not selling anything. What always gets their attention is when I ask if their OD 'hunts'. Almost always the answer is something like 'yes and the dealer has robbed me a couple of times and it still does the same thing'. They listen closely after that.



This fact is also in evidence from the new guys here that have many of the same questions (that I did) when joining TDR.



If you don't already, get the word out. It helps us all.



1stgen

James

 

[Fire Marshal Bill]

Thanks for the info. I will clean the evaporator and check to see that the door is operating when i switch to max a/c.



TDR has helped me with several problems and provided a wealth of info for me over the last year. I have my TDR sticker on the back window and tell people about it when the opportunity arises.

 

[JGorombey]

Mine doesn't increase any when I swich from A/C to MAX A/C as far as volume of air is concerned, but it does get much colder.

 

[TKingsbury]

If you switch it to max a/c with it running and then look into the vent on the right side of the hvac box, you will be able to see some of the evaperator. You could also use a small mechanics mirror to look inside to see how bad it is plugged. I looked at mine yesterday, and it has quite a bit of leaves and stuff in there. If you are gonna cut a hole in your box to clean it, I was looking and thinking the hole should be made in the bottom so the cover plate won't be as noticeable. This is just my suggestion, cause I'm a little more concerned about asthetics than some. Personally, I'm just gonna clean the case when I do my heater core here shortly.

Travis. .

 

[tugboatphil]

The coolant valve is turned off when selecting Max A/C as well as the above stated fact(s)



Scott (under the alias of Tugboatphil)