AC doesn't work on MAX!!!
Thread Starter
|
Cargo Master
Joined: Jan 2002
Posts: 2,079
Likes: 11
From: LA and CO
AC doesn't work on MAX!!!
Guys,
My AC doesn't blow any harder on the max setting like it should. Also, when it's on max and I accelerate moderately the air starts to blow out of the defrost vents, if I lift it then blows out of the defrost vents then the floor then the dash like it should.
Any ideas?? I know it's vacuum related. Is the selector switch in the dash a vacuum switch or electric? Is there anything under the hood specific? Or should I just start tracing vacuum hoses?
Any help is appreciated.
John
My AC doesn't blow any harder on the max setting like it should. Also, when it's on max and I accelerate moderately the air starts to blow out of the defrost vents, if I lift it then blows out of the defrost vents then the floor then the dash like it should.
Any ideas?? I know it's vacuum related. Is the selector switch in the dash a vacuum switch or electric? Is there anything under the hood specific? Or should I just start tracing vacuum hoses?
Any help is appreciated.
John
Elder User
Joined: Jan 2002
Posts: 555
Likes: 0
AC doesn't work on MAX!!!
Hi John, I'm just guessing but you may have a couple of problems. One is the fact that maybe your blower resistor may be bad causing your lower speed on max. When you switch to max there is a bypass that puts a full 12 volts to the blower fan.
Yes a vacuum problem is a possibility, try checking for a line off under the hood, this has been a common fault that I have seen.
If all this fails, you may have to dig deeper to find the problem...let us know how you make out.
Yes a vacuum problem is a possibility, try checking for a line off under the hood, this has been a common fault that I have seen.
If all this fails, you may have to dig deeper to find the problem...let us know how you make out.
Senior User
Joined: Aug 2000
Posts: 264
Likes: 0
AC doesn't work on MAX!!!
Check your vacuum line to the recirc vac motor which is located on the passenger side of the engine compartment up against the firewall. It's usually a white pvc vacuum line. you can check it with a hand held vac tester/brake bleeder. That line runs to a connector located at the very bottom of the dash right over the center of the tranny hump- easy to get to. Disconnect that connector (there will be 5 lines) and plug one end of the white line and test it. Also check the vac motor with the tester and make sure it holds a vacuum. If that's not it, check the other lines and especially your vac canister.
New User
Joined: Jul 2002
Posts: 7
Likes: 0
From: Fort Worth U S A
AC doesn't work on MAX!!!
>Check your vacuum line to the recirc vac motor which is
>located on the passenger side of the engine compartment up
>against the firewall. It's usually a white pvc vacuum line.
> you can check it with a hand held vac tester/brake bleeder.
> That line runs to a connector located at the very bottom of
>the dash right over the center of the tranny hump- easy to
>get to. Disconnect that connector (there will be 5 lines)
>and plug one end of the white line and test it. Also check
>the vac motor with the tester and make sure it holds a
>vacuum. If that's not it, check the other lines and
>especially your vac canister.
Had the exact same problem on my '94 XLT.., the line leading to the vac motor had deteriorated. I was able to cut out the bad section & replace it with some chainsaw fuel line. Works like new now.
Good luck.
>located on the passenger side of the engine compartment up
>against the firewall. It's usually a white pvc vacuum line.
> you can check it with a hand held vac tester/brake bleeder.
> That line runs to a connector located at the very bottom of
>the dash right over the center of the tranny hump- easy to
>get to. Disconnect that connector (there will be 5 lines)
>and plug one end of the white line and test it. Also check
>the vac motor with the tester and make sure it holds a
>vacuum. If that's not it, check the other lines and
>especially your vac canister.
Had the exact same problem on my '94 XLT.., the line leading to the vac motor had deteriorated. I was able to cut out the bad section & replace it with some chainsaw fuel line. Works like new now.
Good luck.
New User
Joined: Mar 2002
Posts: 10
Likes: 0
From: Newton USA
AC doesn't work on MAX!!!
A couple of months ago, my fan only ran on low and high. There is a resistor block with about five wires going to it that protrudes into the air plenum under the hood. The resistor block can be removed with one screw. On my truck, most of the terminals at the connector were badly corroded. A complete fix was made by sanding and cleaning the contacts. It is a bit easier if you remove the resistor block.
More Turbo
Joined: Jul 2002
Posts: 612
Likes: 9
From: south texas
AC doesn't work on MAX!!!
>Guys,
> My AC doesn't blow any harder on the max setting like it
>should. Also, when it's on max and I accelerate moderately
>the air starts to blow out of the defrost vents, if I lift
>it then blows out of the defrost vents then the floor then
>the dash like it should.
>Any ideas?? I know it's vacuum related. Is the selector
>switch in the dash a vacuum switch or electric? Is there
>anything under the hood specific? Or should I just start
>tracing vacuum hoses?
>
>Any help is appreciated.
>John
So, John what did you find out? After surfing here for a while I see that others encountered the same issues I just did. Mine is a 93 F-150 5.0 4x4 and it does the exact same thing. Wish I had found this site but already converted from R-12 to 134a ahh oh well...hey thanks John for your reply......Chinookman
> My AC doesn't blow any harder on the max setting like it
>should. Also, when it's on max and I accelerate moderately
>the air starts to blow out of the defrost vents, if I lift
>it then blows out of the defrost vents then the floor then
>the dash like it should.
>Any ideas?? I know it's vacuum related. Is the selector
>switch in the dash a vacuum switch or electric? Is there
>anything under the hood specific? Or should I just start
>tracing vacuum hoses?
>
>Any help is appreciated.
>John
So, John what did you find out? After surfing here for a while I see that others encountered the same issues I just did. Mine is a 93 F-150 5.0 4x4 and it does the exact same thing. Wish I had found this site but already converted from R-12 to 134a ahh oh well...hey thanks John for your reply......ChinookmanTrending Topics
More Turbo
Joined: Jul 2002
Posts: 612
Likes: 9
From: south texas
AC doesn't work on MAX!!!
yeah-wohoo! cold air again...yeah got burned for converting to R-134a & feel silly for listening to local wrench but ....that's life...a 5 inch piece of ty-gon tubing spliced in the outside air vacuum motor now works and the A/C is back to normal.....I like this site! lotsa good info.......Now to chill once the dash is back together..hmmmm..where these extra screws go.....;-) FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Thread
Thread Starter
Forum
Replies
Last Post
G550_Capt
Excursion - King of SUVs
11
Jul 14, 2011 05:27 PM
