a/c problem

[isenegger]

i noticed that when i accelerate or go up a hill the a/c makes a hissing noise and goes form blowing out the vents to blowing out the defrost. im guessing its a vacuum leak and making the door open/close on me. anyone else noticed or had this problem? any fixs? thanks!

[Richy04]

Actually, mine will do this under heavy acceleration sometimes. To me it's simply a lack of vacuum to maintain the proper amount needed to keep the vacuum servos from slamming shut. If you want you can add a vacuum accumulator to keep a reserve of vacuum in the system. The EATC o-rings may be leaking as well, there is a fix located at the top of the page on how to repair it, but if your eatc is working, I would leave it for now.

[isenegger]

ok cool i might add a vacuum can somewhere. if so where do i tee into?

[Stranger in the Black Sedan]

I drive the hell out of my car from time to time and it does not do this, so I would say you have a leak. Sounds like when the engine is at a lower vacuum condition that factoring in a leak and inherently low vacuum, can no longer hold the damper open or closed, wherever its supposed to be. Adding vacuum cans sounds like a crazy bandaid fix.

[isenegger]

ok well on my 97 f250 it was doing something similar so i unhooked the flapper arm from the vacuum thing and zip tied it shut. so now it blows out the vent no matter what. i can switch it to def and it still blows out the vents. cool enough for me for the summer. can i do the same on this car?

[Wires]

ok well on my 97 f250 it was doing something similar so i unhooked the flapper arm from the vacuum thing and zip tied it shut. so now it blows out the vent no matter what. i can switch it to def and it still blows out the vents. cool enough for me for the summer. can i do the same on this car?

You could, but you have to remove the dash to get to the actuator. Before I fixed my EATC module, I looked it up in the service manual. The first step for servicing the actuator is "remove dash - see page xx"

Chances are, fixing your EATC module (see sticky thread) will solve your problem.

EDIT: There's a thread here about how someone installed vacuum "jumper hose" to keep the actuators set for "dash vents" all the time. Someone had a bad EATC module, that wasn't the O-rings.

[isenegger]

well thats good info about the location about the actuator. i didnt know it wasnt easy to get to. i just dont want to remove the dash. i guess ill do the jumper mod till that quits.

[Wires]

I'd try the o-ring fix. It's a common problem, as you can see from the other replies and the sticky thread.

The guy that had to install the jumper hose had some other, more rare problem that kept his valves from actuating properly, so he had no choice until he could find an EATC module.