My AC is speratic

[DriftingMustang]

Ok, so when my AC works it works amazing. when its not it is blowing full blown oven hot. its wierd, on moment it will be blowing cold and then you hear a loud click under the dash (I think) and pow, instant oven. On top of that we've noticed a consistant pattern. you jam on the brakes and it nearly 100% of the time sets it off. turn it off, jab on the gas, roll switch from cold to hot back to cold and turn it on your ice cold again.

anyone have any ideas?

just to clarify if you dont jab on the gas it will usualy just stay full heat.

 

[SmokedRam]

Might be a blend door problem...

 

[DriftingMustang]

Might be a blend door problem...

Whats that. I take it the flap, valve, thingy that hypotheticly exists in my head that closes off hot, cold and anywhere in between.

 

[SmokedRam]

Exactly...its what blocks off air flow from the heater core when switched to AC...and vise versa

 

[DriftingMustang]

any advice? I have no idea how to get to it, where its at or what it looks like.

 

[SmokedRam]

Never had to repair one...but from what I have heard, the dash will need to be removed to get to it...Hopefully someone with a Gen2 that has done the repair will chime in. I really dont want to steer you wrong.

 

[Needaram]

Im thinking maybe a vac line? Check all of em.

 

[reefguy89]

to get to the blend door just drop the blower like 3 screws on passanger side. Reach up there and feel for the door if it moves around pull it out.

 

[DriftingMustang]

Im thinking maybe a vac line? Check all of em.

if this is the case, im going to feel ******** because i just fixed an ac problem on my 94 mustang involving a vacuum line, it was stuck on the defrost vent.

 

[DriftingMustang]

to get to the blend door just drop the blower like 3 screws on passanger side. Reach up there and feel for the door if it moves around pull it out.

sounds easy enough. then what? also do you have a picture or something to show me exactley where?

 

[KdkGrizz]

Hey everyone. Has anyone experienced the problem of the Vents switching to defrost when the truck is under load. Or shifting up through the gears? Usually it's at low rpm and you are accelerating. After it trans gets up to over-drive it's fine until a hill or something that cause load on the engine. With a hot summer coming and towing my camper and boat the wife will be intolerable without her A/C even for short periods of time.

Need advise......

Oh on the blend door issue check out HeaterTreater.net

 

[Bigtman07]

Hey everyone. Has anyone experienced the problem of the Vents switching to defrost when the truck is under load. Or shifting up through the gears? Usually it's at low rpm and you are accelerating. After it trans gets up to over-drive it's fine until a hill or something that cause load on the engine. With a hot summer coming and towing my camper and boat the wife will be intolerable without her A/C even for short periods of time.

Need advise......

Oh on the blend door issue check out HeaterTreater.net

The switching vents is caused by a bad check valve in the engine compartment. Little 6 dollar part.

Ok, so when my AC works it works amazing. when its not it is blowing full blown oven hot. its wierd, on moment it will be blowing cold and then you hear a loud click under the dash (I think) and pow, instant oven. On top of that we've noticed a consistant pattern. you jam on the brakes and it nearly 100% of the time sets it off. turn it off, jab on the gas, roll switch from cold to hot back to cold and turn it on your ice cold again.

anyone have any ideas?

just to clarify if you dont jab on the gas it will usualy just stay full heat.

Sounds like the blend door. And if yours is a 99 then you should have a stepper motor that controls when the door opens and closes. Since you say it is intermittent I will almost guarantee that your motor is going bad and not moving the door. So to replace that you will have loads of fun.

 

[Robstar]

The switching vents is caused by a bad check valve in the engine compartment. Little 6 dollar part.

Any info on this check valve? Part number? Some pics showing which one would be helpful too!

*Sorry if thread jacking, that is just the exact problem were having!

Robbie

 

[Bigtman07]

The only way I know to find the valve is to take them out one by one and blowing through them. It could be caused by any one of them. Not really on more often than another.

 

[Jimbo]

Any info on this check valve? Part number? Some pics showing which one would be helpful too!

*Sorry if thread jacking, that is just the exact problem were having!

Robbie

Go to O'reilly's....or your favorite parts store.....look on the HELP aisle. They are usually close to the master cylinder caps and gaskets etc.