On my wife's 03 expedition, the a/c blower stops blowing for a couple of seconds when its on Max A/C, but then comes back on. It wont do this when its on the regular a/c setting. This only happens to the vents in the front. The rear vents never stop working. The a/c is cold so I dont think that it needs to be recharged. Has anyone ever had something similar happen?

 

Since it only does this in the MAX A/C position, I would venture to guess the problem is within the selector switch. If it were the blower motor or wiring, then the blower would stop in other switch positions as well.

 

does it completely stop or does it start coming out the defrost vents, and only when the truck is under a load ( EX: taking off from a stop/passing/going up hill)

 

It completely stops coming out the front vents. Nothing comes out the defrost vents when this happens.

 

I drove it yesterday and realized that the fan starts blowing as soon as I let of the gas. Its that under a load it cuts out. It acted fine when I was in regular ac.

 

I would venture to say it is a vacuum leak somewhere since it only does it under load, but you say the blower stops completely and doesnt switch to defrost then back to vent so Im not sure now. The ones Ive seen with a vac leak stops blowing out the vents and starts to come out the defrost when under load, then back through the vents when off the gas (no load)... like mine does.

 

I also thought that it could be a vacuum leak, but it only does it on Max a/c and not on normal a/c when under a load. This is confusing. Thanks.

 

The reason it does it ONLY on MAX a/c is that the fresh air door or "recirculation door" (whose job is to let fresh air in, or recirculate the cabin air) is malfunctioning.

This door is actuated in MAX a/c on the selector switch. If the vaccum line going to it is rotted or has a leak, the doors will not close. I believe it is also actuated under heavy load (accelerating) in order to keep the cabin cool. Not familiar with the 03, but check the passenger side engine compartment for vacuum hoses and see if any are leaking. (the ones going to blower assy)

 

Okay I'm game and will ask the question. How does a malfunctioning fresh air door make the blower motor turn off?

 

My comment was based on the fact that I'm not convinced the blower stops for a few seconds and then starts again. Who knows, maybe it does. The blower motor has no effect from Max A/C to normal A/C. If the blower works in normal, it will work on max a/c right?

Possibly he has an automatic temperature control head unit and it is malfunctioning? Otherwise with manual *****, it shouldn't matter what the switch setting is...the blower is either working or it is not. If it doesn't work on high, low or middle etc, then we can deduce a blower resistor, but between max a/c and normal we should see the same behavior.

 

Right, unless the selector switch has a bad contact inside when it's positioned at Max A/C. I've already suggested the switch to him as the problem and have yet to hear back if he's checked into it or not.

 

Hi

I have an 04 expedition Eddie B

When I turn max ac on go underload it cuts out comes out the defroster!!!!

Please can I have some guidance into this issue!!!

Thanks
Matt

 

Read post #6.

 

most common place for the vac leak is under the battery tray.

 

Mine still has cold air coming through the vents though with a leak surley it would not be cold anymore ?!