A/C issue

[CTL2002]

Blows out defrost when I accelerate and blows out front vent when I coast! My question; Is that an easy fix??

 

[Number Twelve]

That's not an A/C problem. It's an air flow problem. A vacuum motor left of the glove box controls that flap. Vacuum failure under acceleration indicates a vacuum leak. You're looking for a vacuum leak in the air controls...or anywhere in the vacuum tubing in or under the dashboard.

 

[CTL2002]

That's not an A/C problem. It's an air flow problem. A vacuum motor left of the glove box controls that flap. Vacuum failure under acceleration indicates a vacuum leak. You're looking for a vacuum leak in the air controls...or anywhere in the vacuum tubing in or under the dashboard.

 

[CTL2002]

Thanks Will that cost an arm and leg to fix if I took it to a certified mechanic??

 

[Number Twelve]

Certified Mechanic?
I haven't hired a Certified Mechanic since the 1980's!
I don't have a clue how much they cost.
Except, "too much".
I just find it quicker, easier, and cheaper to look at the tubing and find the break, compared to waiting around most of a day for some $100 per hour "professional" to fit a 50 cent repair on a low pressure plastic tube. Or worse, go to a Dealership and pay them $100 to ask a computer what's wrong, tell me what I already know (it's a vacuum leak), and hand me an estimate for the trade-in value of the car.

Maybe somebody else can guess what the retail price of a 1 hour job is.

 

[fordysenior]

If you have any mechanical ability -- lower your glove box and look for the actuators. Follow the tubing (vacuum lines) from the mode selector switch to each actuator. Make sure the tubes are connected and undamaged. Then look at the other side of the actuator. There is a metal arm that moves back and forth. The other end of the arm is to be connected to a plastic fitting which is known to break -- OR the arm simply comes off. By lowering the glove box, you should be able to find 3 of the actuators. You can take visuals on two of them, the third one I had to 'feel' if the arm was connected. YouTube can be a little help. Have a good flashlight handy and stick your head in there the best you can. Also, pull back the center bezel if that helps, it only clips on. Start the engine, move the selector switch to various positions and see if the actuators are working. Not hard to do, 20 minutes effort. And there is a fourth actuator on the drivers side -- I found my problem before having to locate it.

 

[TechGuru]

Bad check valve letting the vacuum out of the system when accelerating.

 

[Number Twelve]

Bad check valve letting the vacuum out of the system when accelerating.

I've never seen that happen. It's a perfectly valid suspect, but I have only ever found broken tubing, disconnected tubing, leaky diaphragms in the vacuum motors, and a rusted through vacuum canister on a '65 mustang. (It was sheet metal and mounted in the front passenger side wheel well.) The vacuum can in your car is plastic and mounted by the A/C fan.

Don't forget the hot water valve on the passenger side of the engine. It has vacuum applied all the time you are not using heat. It gets knocked off sometimes. That's what was wrong with my car. I have no idea who knocked it off or what they were doing at the time. Might have been spark plugs, the EGR valve near the air intake. Oh yeah, that has a vacuum tube, too. And the brakes have a vacuum connection on the master cylinder, vacuum assist for the brakes.