I'm betting one of you geniuses can help me out so here it is....

My Wife has a 1998 Ford Explorer with the Electronic Automatic Temperature Control (EATC) that started having problems lately. With the AC on and the car medium to hard accelerating the air from the front vents switches to the top defrost vents. As soon as she releases the accelerator the air switches back. I’m assuming it is a problem with either some sensor or one of the controls vacuum lines but everything looks plugged in and operating. She also noticed around the same time, that the fan does not blow as hard & the AC isn’t as cold.

Thanks in advance,
Bill

problem is......



























its a ford

sorry bill. someone else can heeelp

The vent controls are powered by engine vacuum. Most all cars/trucks set up this way need a vacuum reservoir to handle extended loads where engine vacuum is concerned. In short you have a vacuum leak where the system feeds the vent controls. It is likely under the hood or in a fender well. A vacuum line off / damaged directly in line with the vent feed. The amount of vacuum needed is small, so its likely the engine still idles smooth. The leak could be under the dash but not as likely as under the hood.

Thanks for the advice, that makes sense. Now my next question would be how best to check for a vacuum leak?

1st check the vacuum canister with ****gasp**** a vacuum pump...Avaliable at your local Flaps and many fine tool stores.

If it holds, the start checking the colorful little plastic lines that run to it with ****GASP**** a vacuum pump...Available at Sears, Harbor Freight and many other fine stores.

In the end, tell her to stop having Soccer Mommy Races with the other mommies in their SUVs. Her ego will get over it.

And if you didn't drink such shitty beer that kills your grey cells you would have already figured this out............

On my 914, I check for vacuum leaks using handheld propane (camping type). Spray the stuff all around the hoses that might be cracked/leaking/etc... The engine will stumble (but not stall) if propane gets in the air/fuel mixture.

-pt

That makes me wonder what the LEL is for propane. You know, the lower explosive limit or the the percentage mixture required for an explosion.

Damn, I so hate going to Harbor Freight

While I'm there do you need me to stop by the fabric store next door and pick you up some denim for another pair of those daisy dukes you love soo much?

I think the lower volume of air from the fan is also associated with said vacuum leak.
One of them shitty little plastic manifolds my have a crack.
My dad had this problem with one of his Fords.
Ended up selling it instead of fixing it. Bought a Dodge now he just shovels gas dollars at it.

My teener says "What's vacuum line"?