max a/c prob. stops blowing when driving

[daveanton]

hey guys quick question.. a/c works great but for some reason max a/c seems to be fine when its first turned on but as soon as you start driving it switches from the dash vents to defrost vents. if its switched back to panel/floor then back same thing.. any ideas??

 

[kburrows]

my 97 eb x does the same thing. kind of anoying so i leave on panel/floor and it never happens. is panel floor recirculated air? i would like to get this fixed. I'll be watching for answers. thanks

 

[witchdoctor]

The problem is a vacuum problem. Look underneath the passenger side front, just in front of the wheel. There is a panel you will have to remove. Underneath is a black plastic globe about the size of a softball. There will be 2 or 3 vacuum lines running to this. Check that they are attached, and trace them to see if they are leaking or broken. If they are fine, then take off the black globe, which is the vacuum reservoir, and shake it. If you feel a ball rolling around inside, you must replace the reservoir. About $20 at fordpartsnetwork.com. You will need to tell them if your reservoir has 2 or 3 lines connected to it.

 

[wpurple]

Replace the vacuum canister under the wheel well aprin and you'll be all set.

(looks like a black plastic ball)

 

[ExplorerDMB]

I would check the lines first.

-Drew

 

[Brian_B]

I don't know about the newer vehicles at all, but on two older fords the vacuum line was just unplugged from the actuator for the little door for the air. Check the lines like he said.

 

[kburrows]

Where is the panel. Please be more specific. Do you have to remove anything before you get to the panels? I am very mechanical but didn't see the panel.

 

[Brian_B]

.....Look underneath the passenger side front, just in front of the wheel. There is a panel you will have to remove....

Quote from post number 3.

 

[kburrows]

ok, lets get real simple. Is this panel located in the engine compartment? Do I have to lift the hood and then look for this panel? Do I have to remove the radiator overflow? Do I have to remove the winshield washer reservior? Do I access this panel from the inside of the car behind the glove box? Now really, could someone who has found this vacuumn reservior tell me exactly where it is. I would really appreciate it. Thanks

 

[Brian_B]

On the older rangers its under the passenger side of the dash. I think (not sure) that you have to go through the glove box on the newer explorers. Sorry not much help there.

 

[witchdoctor]

You get to it from underneath the truck. It will be directly beneath where your airbox sits in the engine compartment, but you cannot access it from the engine compartment, but from underneath in front of the wheel well.

 

[kburrows]

ok, I didn't slide under the truck and look for it. No wonder I couldn't figure out where it was. I will be checking it out first thing in the morning. thanks witchdocter.....

 

[kburrows]

witchdoctor, found it very easily. mine has 2 hoses. both look fine and the lines don't look cracked or worn. the vacuum canister didn't have anything ajar in it when i shook it. i trased one of the hose back and it looked ok. the second hose went underneath the ac and looked to be heading toward the firewall. I wasn't able to trace it all the way. should i replace the vacuum canister and see if that fixes it or should put a hand vacuum pump on the hoses and check them? one other thing, how do the hoses connect to the vacuum cannister? I pulled really hard and they wouldn't come out. I am assuming they are not leaking at that point since they didn't want to come out. please share your thoughts. thanks, Kevin

 

[witchdoctor]

That's funny, my lines pulled right off. It is possible that the lines and the canister are fine; I would look inside the truck under the passenger side dash. Somewhere in there is where that second line connects to the vent controls, and it often comes loose there. If that is not the case I would go ahead and replace the canister.

 

[wildthings]

no vent air output?

I have a related question... if anybody is still watching this thread? I rarely get any air coming out of the vents or the bottom vents. (but sometimes, do) I have vacuum at some part in the cabin area, because the inside/ outside actuater is working fine. So I am thinking maybe the switch or the actuator that controls the direction of the air flow??? Where is that actuator? 1999 Explorer
Thanks

 

[wildthings]

no vent air output?

I have a related question... if anybody is still watching this thread? I rarely get any air coming out of the vents or the bottom vents. (but sometimes, do) I have vacuum at some part in the cabin area, because the inside/ outside air actuater is working fine. So I am thinking maybe the switch or the actuator that controls the direction of the air flow??? Where is that actuator?
Thanks

 

[Papa]

Are you refering to the blend door?
http://www.explorerforum.com/forums/showthread.php?t=153844

 

[zims666]

does anyone know the part number for the vacuum reservoir (black globe thing).
i cant seem to find it on rockauto.com or trademotion.com (fast parts network).
or, does anyone know where i can buy a replacement.
i was in and accident that damaged the front passenger side and knocked the vacuum reservoir loose. it must have been sitting on an exhaust pipe because its melted pretty bad... no my heat is stuck on defrost.