AC stops blowing on acceleration

[fgross2006]

I have had this issue for awhile. When I accelerate the AC stops blowing out the front vents and blows out the defroster for a few seconds, then goes back to the front vents after I level off my acceleration.

I found this video on U-Tube but this guy has the same issue with an E350. He said he had to change a check valve and a AC reservoir. Cant be the same procedure for a E350 and a 84 LX. Although both Fords the setup has to be way different.

Can anyone tell me how to fix this AC problem? What part is failing or not functioning correct?

heres the E350 vid

[ZephyrEFI]

Sounds like a vacuum problem to me. The system is designed to default to defrost if it's not seeing vacuum. If you look at the diagram under the hood it should show you where those parts are.

Sent from my XT1650 using Tapatalk

[Haystack]

There is a wot cutout switch on most a.c. systems, depending on how much throttle you use, it usually kicks in around 1/2 throttle.

And yeah, sounds like low vacuum. Vacuum keeps the heater stuff open.

[fgross2006]

There is a wot cutout switch on most a.c. systems, depending on how much throttle you use, it usually kicks in around 1/2 throttle.

And yeah, sounds like low vacuum. Vacuum keeps the heater stuff open.

does an 84 have a vacuum reservoir? I cant locate it on my car.

Vacuum line from main Tee to the 3 way check valve is new. The check valve is original as far as I know. Theres 2 lines coming off the tee. I know one goes to the HVAC panel. Not sure where the other goes.

[ashley roachclip]

Ac canister is inside the fender passenger side .

[KevinK]

Start at the firewall top on the passenger side. You should find a check valve/tee with a vacuum line. It will be a round disk type black or black and white. Next follow the one line along the right fender apron. About 3/4 the way to the front, it will go into the fender well. The resvoir mounts inside the fender well with self tapping screws. Look for a black round ball. You need both the reservoir and the check valve connected. Some models use the thin nylon tubing in between for a vacuum line.

[fgross2006]

Ac canister is inside the fender passenger side .

I remember the canister being inside the wheel well on passenger side when I was installing a new cruise control cable a few years back. I assumed that was part of the cruise control system at the time.

[KevinK]

I remember the canister being inside the wheel well on passenger side when I was installing a new cruise control cable a few years back. I assumed that was part of the cruise control system at the time.

Cruise is on the drivers side. Vacuum canister is on the other side.

[steam_mill]

Are you sure it is coming through the defrost vents? Does your HVAC fan turn off when you go above half throttle?

On a hot summer's day, when the AC is on, if I'm in 5th gear for example and hit an incline where I have to give it more throttle, my AC will also go off. Air may be coming or appear to be coming from the defrost vents. When I let off the throttle, it all comes back. My understanding is that this I part of the TSAD that never made it to production.