regular a/c is warm, max a/c is cold

[keane728]

what would cause the regular a/c setting to blow warm air but the max ac to blow really cold air like there/s nothing wrong? I replaced a vacuum controlled valve under the hood a while back that looks like it controls flow to the heater core. could that have been it?

 

[srteach]

Your AC is low on R12 / R134a, or you have a leak in the system. Have it checked and filled. Do it yourself if you have the equipment and knowledge.

 

[snoman6115]

srteach is probably completely wrong. ide bet anything its your blend door. try this first http://www.blenddoorfix.netfirms.com/ and if that dont work you gotta do what i did and take your dash out and replace it. to replace it the kit is only $15(shop around some places will charge like $30) but took me like 7 hrs to tear the dash out and fix the door and re-install

 

[v8318cid]

I can't say that either suggestion is right or wrong, but here's something to consider. According to the owner's manual on several of the Fords I've driven, if you set your controls to Max A/C, the temperature setting has no effect. While I disagree with this based upon my own experience, it does seem like when you're running in Norm A/C you're getting additional heat from your heater core. What I would suggest, if you haven't already fixed it, is to obtain a vent thermometer. Stick it in the vent nearest the evaporator, or in one of the center vents if you aren't sure. With the A/C off and the temp selector at full cool, check the output air temp. If the temp is significantly above normal air temp, you're bleeding off heat. At this point, check the blend door like was mentioned above. If the temp is roughly the same as outside air, you may be low on refrigerant. A 134a system is more likely to lose efficiency when moderately low than a 12 system since it isn't as efficient at removing heat when used on systems between 94 and 2000. Newer systems seem to be designed better and are less susceptable to this problem, at least in my opinion.

 

[shane96ranger]

if you set your controls to Max A/C, the temperature setting has no effect. While I disagree with this based upon my own experience

When it's on Normal A/C it brings in fresh air from outside the cab, Max A/C recirculates the air already in the cab. So if it's 90 degrees outside and pulling that air inside then it will be warmer than recirculating the already cooler air that's in the cabin. That's why you hear a door shut under the dash when you move it to Max A/C.

 

[keane728]

warm a/c

it is definitely pushing warm air when i have the a/c on and when it is just on the vent without the a/c. i hadn't noticed this problem because i always use the max a/c setting. If it is pushing warm air with the vent on does that mean that i have a temp control problem or the vent doors might not be working? the air that it's pushing seems hotter than outside air.

 

[shane96ranger]

Like Snoman said above, it's more than likely a blend door problem. Did you check into that at all?

 

[keane728]

warm a/c

i just talked to my mechanic and he said that with this year model(97) it was probably a blend door also. he said that the heater core valve will cut the water flow off only when on max a/c and that's why there's such a big difference with regular a/c since the blend door's not working. same thing when using the vent. it's letting all the warm air in and not blending any cool air. with this year model that means tearing the whole dash apart so i'm not sure what the next step is. i've got a guy that wants to buy it and he drove it already so max a/c might be it.

 

[shane96ranger]

i just talked to my mechanic and he said that with this year model(97) it was probably a blend door also. he said that the heater core valve will cut the water flow off only when on max a/c and that's why there's such a big difference with regular a/c since the blend door's not working. same thing when using the vent. it's letting all the warm air in and not blending any cool air. with this year model that means tearing the whole dash apart so i'm not sure what the next step is. i've got a guy that wants to buy it and he drove it already so max a/c might be it.

Did you look at the fix posted above in the link? No need to pull out the dash if it's the problem in the post, which is likely the cause. I might be wrong, but I'm fairly certain the heater bypass works under all A/C conditions.

 

[keane728]

warm a/c

which fix are you referring to?

 

[shane96ranger]

which fix are you referring to?

This one that Snoman posted (you have to click on it) http://www.blenddoorfix.netfirms.com/

 

[v8318cid]

Shane96ranger, I wasn't referring to the recirculation door. I was referring to the temperature door (blend door?). According to Ford, if your A/C is running on MAX, they say that adjusting the temperature knob has no effect. Of course, if what was posted above about the heater control valve operation is true, that would make sense. My 92, nor either of my two 86 tbirds have had that type of valve.

 

[shane96ranger]

Shane96ranger, I wasn't referring to the recirculation door. I was referring to the temperature door (blend door?). According to Ford, if your A/C is running on MAX, they say that adjusting the temperature knob has no effect. Of course, if what was posted above about the heater control valve operation is true, that would make sense. My 92, nor either of my two 86 tbirds have had that type of valve.

OK, that makes sense. My bad,I should have realized that.

 

[v8318cid]

No worries. I'm not always the greatest at explaining things correctly.

 

[modelageek]

which fix are you referring to?

update your signature/profile so that it has all the info about your truck and location..you can use mine as a template