Blower keeps switching between dash vents and defrost when taking off..

[Cobraguy]

This is an easy fix...but may take some time. Just start replacing all the vacuum lines to your HVAC system. Your car is old...this should be done anyway. Check your vacuum reservoir for leaks with a vacuum pump. (you should borrow one from O'Reilly's, etc to do this anyway) The only caveat to this is if you have a leaking vacuum switch or vacuum line in the controls, or vacuum motor. Then you could be looking at some work.

 

[Deleted member 128963]

My explorer has a mind of its own it seems.... When I have it set on ac or max ac (havnt tried other settings) it blowes through the dash vents but it seems like when I take off from a stop it switches to defrost for a minute then back to the dash vents once I get to crushing speed. Kind of a huge pain since I stop/go about 500 times a day delivering mail! Lol.

I'm guessing a vacuum issue somewhere but it's been a really long, and very hot, day!! Im completely brain dead at the moment and hoping to figure this out before work tomorow.

I recently did a ton of work on the top end of engine and replaced the entire AC system including the evaporator and condensor.
I looked under the hood but not seeing anything visually.

Do a search for EATC on youtube. For 5$ in parts you can rebuild it yourself.

 

[Turdle]

How to: - 2nd Gen NO AC ( or heat) FROM VENTS!!! A "How to" what to look for thread

Here is what to look for if you have a 95-01 with cold ac, and hot heat, but it only blows from the defrost vent. IF YOU HAVE COLD AND / OR WARM AIR BLOWING FROM DEFROST DUCT ONLY THIS THREAD IS FOR YOU!!! I will immediately delete all ac cooling questions without answer-let's stay on track...

www.explorerforum.com

Just gonna throw this thread in here for stimulation

 

[MartyD]

Our '07 Grand Marquis had the same problem of switching to the defrost vent and would change under load. It grew gradually worse until finally it was defrost only. Took it to the Ford dealer (since there are no more Mercury dealers) and the leak was in the digital control unit in the dash. $1200 dollars later and it worked again! Sheesh!

 

[Weedman]

Are you sure it's switching vents or is it maybe just blowing warm while you accelerate? If it's like the old 5.0 Stangs, the AC was designed to cut out under hard acceleration in order to maximize power to the wheels. Quite a few cars have this feature. IDK if it can be defeated.

No definitely goes from dash to defrost under acceleration and back to dash at idle