Vacuum line break - 2000 Chrysler Concorde

You have a vacuum leak in the system causing several problems.
You will need to inspect vacuum lines from motor to brake master cylinder and to the A/C system. Just run your fingers down the lines looking for a burn or a brake in the line. Once you find the problem you can use a two inch piece of rubber fuel line or vacuum line to do the repair. The part should cost you no more than a Dollar if they charge you anything at all for a small piece of rubber.

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Maybe the vacuum line to the selector is disconnected/leaking /bad. Most of the vacuum controlled systems I have worked with also have a vacuum amplifier somewhere under the hood that increases the amount of vacuum going to the selector.

More than likely vacuum problem--Supply line runs from vacuum reservoir to dash control panel--no vacuum on that line will cause control doors to stay in defrost mode--lines are plastic, and were bad to break from age. If lines look OK be sure vacuum is being supplied to line--from reservoir and to reservoir. Lastly line could be off dash controller or a bad dash controller or lines and or vacuum pods downstream--usually you can hear inside leaks. NOTE: defrost is default mode.

You can also vacuum the fluid through the system to the back with a vacuum bleeder attached to a rear bleeder.

Check the condition of the pads, disks, and operation of both. They should be freely moving.Also check that your brake lines are free of air and that your fluid is clean.
Also check that the vacuum line to your brake servo is intact, and that you have adequate vacuum to your servo.

The air controls in the heat/AC system are vacuum operated. When the controls don't cause the air flow to shift it is normally caused by lack of vacuum to the air flow system. This is normally caused by a break in a vacuum or a vacuum line that has come loose from a connection, usually under the hood. These vacuum lines are small black plastic tubes about 1/8 to 3/16 in diameter. My experience has been that places under the hood where these lines are exposed to high heat causes them to get brittle and break or crack. I have found lines that are between the battery and fire wall that don't get much air flow and are heated by the battery are a likely place to look. Look for the line that goes through the fire wall. that is likely the damaged line. Trace it back to find the crack or break. If you find this is the cause, replace all the section of line that is brittle. If you don't do that you will have the same problem again very soon. You can splice sections of this tubing with rubber hose of the proper inside diameter. Good luck.

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Gaker

There is a single vacuum line that goes threw the firewall that feeds the controls, that will actuate the plenum doors. This tends to break under the hood. If you find the vacuum canister (ball) Make sure it is not cracked first. then follow the vacuum lines and you will find the line that goes into the firewall. Usually a direct connection. Fix it if you find a break. If it broke in the cabin, then it is easier to run a new line than it is to find the break.

Hello, Check other Vacuum lines for leaks. If you have a 4x4, they can have Vacuum operated hubs and a leak anywhere will draw down the Vacuum. I found most pumps running at about 21psi. Check for a Vacuum Reservoir. The older models used one looking like a coffee can and they would rust on the bottom and leak.

If you take off a vacuum line and use a hand vacuum pump, you should easily find a leak on one of the remote lines. Another test idea is to remove the Vacuum pump lines, put in soapy water, and pressurize with about 3 PSI. Any vacuum leaks will blow bubbles and soapy fluid. Its your choice on what to do. I would reserve the soapy water for a line I find to leak with a hand Vacuum pump.

Many of the people wih your problem replaced the vacuum pump and were good to go. But if you can measure the vacuum and find the leak, you may save money on a part you do not need.

You either have air in the line or your vacuum booster needs replaced. Try to bleed them first. Then pull the vacuum line of the booster and see if it makes a change. Good luck.

The controls on your Astro are operated by vacuum from the engine.
Because vacuum drops as the throttle is opened to maintain vacuum to those controls a vacuum reservoir is used.
You have a leaking vacuum line causing your problem.
Look for a black line about 1/8th inch diameter coming out of the cab on the left side into the engine bay. You will have to look under the cowl over the engine and you will likely find a rotten piece of plastic vacuum line. Cut the old plastic well back as it will break again soon from heat.Get a piece of rubber vacuum line from your local auto supply that will slide snugly over the plastic. This is where your problem will be at a 95% probability.
If you have any further questions please place them in "add comments" and I will respond to help.
Thank you for using FixYa!

KL