ac blower cuts out when accelerating
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From: Dallas Ga
ac blower cuts out when accelerating
Just got my 94 extended Aerostar back from the tranny shop,that's a whole posting or two by itself, and the ac blower cuts out when the van accelerates moderately or more.It started doing it on the front ac only but now has started in the rear ac also. The blower comes back on as the speed gets steady. I'm thinking the tranny shop may have done something but I not really sure what to look for.Anyone ever experienced this??? I hope the third time is the charm on the tranny rebuild. 94 aero 4.0 w/165000 miles and counting!!!!
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Senior User
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From: Dallas Ga
ac blower cuts out when accelerating
While driving my van I discovered the blower doesn't cut off, but the air comes out of the defrost vent. I'm also not sure about the air cutting off in the rear. It didn't cut off during this latest drive.
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Joined: Aug 2002
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From: Fulton USA
ac blower cuts out when accelerating
Sounds like a vacuum problem. Trace the vacuum lines, follow the diagram label underside of the hood. Not very many lines so you shouldn't get lost. I've got a '93 Eddie Eddie Bauer extended 2WD that the vacuum lines pop off the intake manifold if you let off the starter too quickly. I got some of those squeeze type clamps to cure that problem. The lines connect on the left bank of the engine on top. You should see some tiny lines coming from your front blower etc. Those are for the blend door.
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From: Dallas Ga
ac blower cuts out when accelerating
Thanks for the info. I found the hard vacuum line running to the vacuum control motor was broken. I was able to splice it together and check it. Does Ford sell replacement vac line?
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ac blower cuts out when accelerating
My 97 aerostar with the 3.0 engine has a blower motor that switches to defrost on accel. . I checked AutoZone this morning and the blower motor is 38.99. I will go check the vac. lines and then maybe replace the blower motor as well. The output does not seem very strong when functioning normally and the air flow passes through the defrost for about ten seconds every time I turn the blower on.
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ac blower cuts out when accelerating
The various blower outlet positions are all vacuum controlled. The fact that the positions change under varying engine load indicates a vacuum leak in the system. The most likely cause is a loose or broken vacuum line that has been disturbed during engine maintenance. Check your engine compartment carefully first. If all appears in order there, the next most likely cause would be a damaged vacuum line under the dash to the HVAC unit itself or a weak vacuum actuator motor on the HVAC unit. In rare instances the dash mounted control valve is the culprit. It is also common for pens, coins, etc to slip down the vent registers and block the door within the HVAC unit that directs airflow to the various outlets.
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From: PNW
ac blower cuts out when accelerating
Don't forget about the check valve in the vacuum line to the AC system. It's pretty common for these to fail. It traps vacuum in the AC system when manifold vacuum drops, like when accelerating or climbing a hill. I found a nearly equivalent check valve for about $2 at McMaster Carr. You might need an adapter or two because their check valves have the same inlet and outlet diameters, whereas the stock one has diffent inlet and outlet diameters. I have also seen a similar check valve at a local NAPA. The check valve alone is not available from the dealer. You have to buy an "assembly" for about $70.
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From: South Carolina
ac blower cuts out when accelerating
I had a similar problem on my 1992 about a year ago.
Here I am driving down the freeway 105degrees outside and boy that a/c feels good. Then suddenly no air is coming out, but I still here the blower running. Then I notice that the air is coming out of the defrost vents.... So I reach over and turn it off for a few minutes...then back on, back to normal. about five minutes later the same thing again....so I turned it back off again.. waited a while longer and the back on.. No more problems with it since...
Don't ask me why it did that, but it is definately one of the wierder things this van has done.
-Mike-
Here I am driving down the freeway 105degrees outside and boy that a/c feels good. Then suddenly no air is coming out, but I still here the blower running. Then I notice that the air is coming out of the defrost vents.... So I reach over and turn it off for a few minutes...then back on, back to normal. about five minutes later the same thing again....so I turned it back off again.. waited a while longer and the back on.. No more problems with it since...
Don't ask me why it did that, but it is definately one of the wierder things this van has done.
-Mike-
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ac blower cuts out when accelerating
This seems to be a very common problem with Aerostars, and it all has to do with the vacuum-controlled blend doors. My '88 has weak output on the floor, but otherwise works ok. My '92 wouldn't switch to the floor at all, but works fine on the vent and defrost positions. I've never gotten around to troubleshooting this, but if I finally do (this vehicle has far bigger problems) I'll look at the controls and vacuum lines going to the vacuum motors, and I'm sure I'll find it there.
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