Looking for heat when on MAX A/C

[SWLathrop]

Saw a post last year about getting heat when controls set to "MAX" A/C. Searched everywhere, but nothing comes up. What is the procedure to get warmer air when set to the "MAX" position? Thanks.

 

[lonestar]

Why would you want hot air when the A/C is set to MAX A/C. If you want hot air just turn on the heater. If you want cool air instead of cold, turn it to PANEL instead of MAX.

 

[Jarrett088]

Do want the air not to be as cool? You should have a temp control somewhere. Not sure about the newer one but my 94 has a slide button from cold to hot. You may want to move your slide towards the middle or towards the hot side. The should give you a little "warmer" cool air. This also works when trying to get a little less heat in the winter.

Tim

 

[RedBeard]

On my '96, MAX AC will only blow cold air. Regular AC will allow a temperature adjustment. I always use MAX AC because it recirculates the air and does not allow any fresh air (or exhaust fumes from the pinto in front of me) into the cab.

-RB

 

[addkev]

I know what you are talking about, as I remember it was a vacuum issue. I will try to find it, I remember reading it, but can't recall the fix, but I think it was pretty easy.

 

[Robert]

The '95 and up (not sure of the '94 and earlier) have a heater coolant solenoid that is vacuum controlled. When you put your selector in MAX, it closes the solenoid which prevents the hot coolant from circulating through the A/C - Heater. The vacuum line that goes to it is about 1/8". The solenoid is on the heater line down past the bottom of your overflow reservoir. It has the hose coming off of it which then goes into a rubber connector, more hose then to a 'T'. I disconnect mine down by the solenoid every winter and stick a golf 'T' inside the rubber adapter and tape up the end of the hose going to the solenoid to prevent dirt from getting in to it. It is nice to be able to block off the exhaust fumes from the car in front of you while still getting heat. I posted this same information about 18 months ago.

 

[SWLathrop]

Robert, thanks...

That's exactly what I was looking for. It was your post that I probably read. I like it real cold, but the Social Director doesn't. So it's nice to be able to increase the temp just a little while not trying to cool hot, humid, smelly outside air. Plus, running on MAX is more fuel efficient. Again thanks...

 

[lonestar]

I read the same thread. It it is a vacuum controlled valve that shuts off radiator fluid to the heater core when set to MAX A/C. This is to decrease the temp when set to MAX, not increase. It sounded like you wanted hot air when set to MAX A/C.
The 1st gen did not have this valve and is sometimes used to decrease the AC temp in early X's. I heard it lowers the temp from 4-6 degrees. I had to replace this valve on my girlfriends 95 Ranger. i beleive to use in a early X, you would just have to purchase the valve, cut the heater hose, install valve, and run an vacuum hose to the AC controls to close the valve when set to MAX.

 

[lonestar]

I just reread the post by Robert and I think I understand what you are doing now. Let me make sure though. You bypass the shut off valve to get heat in the winter in the MAX position, instead of constantly heating outside air.

But then SWLathrop confused me again when you said " cool hot, humid, smelly outside air". So what are you trying to do? Cool hot outside air, heat AC air or recirculate hot air? Maybe you like the MAX for recirculating the air, but not the MAX temp. I don't think this will solve that problem. The valve is either open or closed. So then if you leave the valve open you will basically be running the heater and the AC at the same time.

 

[addkev]

Yes, Max is the only setting that recirculates.

 

[Robert]

Originally posted by lonestar
. . .The valve is either open or closed. So then if you leave the valve open you will basically be running the heater and the AC at the same time.

That is basically what you are doing in the Norm A/C mode. The radiator coolant flows throught he heater core when the solenoid is open. The Temp control dial adjusts the blend door from full heat to full A/C and anywhere in between. The problem is Norm A/C mode gets its air from the outside vents in front of the windshield. When you put it in Max mode, the radiator coolant is prevented from circulating through the heater core which does not allow for changing the temperature. There are times that I want to block off a bad smell outside but Max A/C is just too cold. The only two ways to block off the outside air is by putting it in Max or Off. In the winter Max is way too cold and Off is still too cold. I put it in Max and then adjust the temperature up a bit to mix heated air with the air conditioned air. Same thing in the summer time but in reverse. If I want to block off the outside air when it is about 100F outside, Max A/C can sometimes be too cold. If I turn it off it gets too hot. Since I am in Phoenix, I reenable the solenoid in the summer since I want all the A/C I can get. It isn't as important in the winter though when an extremely cold day is 30F.

 

[VairKing]

Does Max A/C recirculate on 1st gen Xs?

 

[RedBeard]

Originally posted by SWLathrop
Plus, running on MAX is more fuel efficient. Again thanks...

Why is that? Just curious because I always use MAX AC.

-RB

 

[mosinman]

Running your AC on max recirculates cabin air instead of pulling in hot outside air to cool. That is why it is more efficient.

 

[mmsdrummer]

Does Max A/C recirculate on 1st gen Xs?

Yes

 

[SWLathrop]

OK, I disconnected the selonoid and blocked off both ends of the vacuum line. It works like a champ. I can now adjust the inside temp for any temperature from 60 degrees on up. Now I can have cool air and the Social Director doesn't get cold.

Running on MAX is more fuel efficient due to the fact that you're cooling already cooled recirculated air, thus the compressor doesn't have to run constantly. If in NORMAL A/C mode, the compressor is pretty much running all the time to try and cool down HOT and HUMID outside air.