Ported vacuum switch what does it do

Question edited for clarity, spelling and add maker.
Question moved to model category.

Help in the link, plus link to specialty forums.

https://www.google.com/search?q=1966+galaxie+500xl+vacuum+diagram

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Overheating is caused by the following:
1. Defective thermostat
2. Clogged radiator with deposits due to age
3. Antifreeze that has not been changed for several years
The ported vacuum switch has nothing to do with the cooling system of your car. It just controls when vacuum gets to a particular part or not.

first off what does that mean? 91 command trac system.
1: light dead in dash. ( means squat)
2: shift lever will not move. (i guess its ok)
3: tires actually do not turn on 4 ends of axles. (guess fails)

we cant guess, what tests fail, you must say.
do you have drive on the front prop shaft,
from transfer case to the front axle.?
91 books are hard to find, but alldata.com does cover it.
ever read the FSM or alldata.com its there.
my guess is you are saying the shift motor is dead/. that it?
this?



if yes, did you do the steps in the FSM book yet>? read it?

1. Raise and support the vehicle safely.
2. Disconnect the vacuum harness and connect a hand vacuum pump to the front port. Apply 15 in. Hg (381mm Hg) of vacuum to the front port and rotate the right front wheel to fully disengage axle shafts.
3. The shift motor should maintain the vacuum applied to the front port for a minimum of 30 seconds. If the motor does not maintain the vacuum, replace it. If the motor does maintain vacuum go to Step 4.
4. Connect the vacuum pump to the rear port. Cap the port for the indicator lamp switch and apply 15 in. Hg (381mm Hg).
5. The shift motor should maintain the vacuum applied to the rear port for a minimum of 30 seconds. If the motor does not maintain the vacuum, replace it. If the motor does maintain vacuum go to Step 6.
6. Remove the cap from the port for the indicator lamp switch and determine if vacuum is present. If present, the shift motor is functioning properly. If not, proceed to Step 7.
7. Apply 15 in. Hg (381mm Hg) of vacuum to the shift motor rear port. Rotate the right front wheel to engage the axle shafts. The axles must be completely engaged!
8. Determine if vacuum is present at the port for the indicator lamp switch. If present, the shift motor is functioning properly. If not, replace the shift motor.

tests: this is just a vacuum servo , called a motor by jeep, its not a motor of any kind its a vacuum servo actuator.
it can be removed and bench tested, easy. just like all servos

Standing in front of the car, the lower left vacuum port on the carb goes to the distributor. The upper left port goes to the vacuum switch for the secondaries. The brake booster screws into the rear base of the carburator. The transmission kickdown plugs into a nipple on the rear of the intake manifold.

1. Check for vacuum passing through the canister purge solenoid all the time. When it is electrically turned off, there should be no vacuum going back to the charcoal canister.

2. Check the hoses to the purge solenoid for being switched around. Manifold vacuum should be going to the top port and line back to the canister on the bottom port.

Basically it won't supply vacuum untill the car has warmed up. The ported vaccum switch is basically a temp. activated switch that will disable everything hooked to it, untill the car warms up.

Is this stock which would actually be a a 305 Camaro with a 4 barrel feed back Quadrajet?
Basically,
Vapor line from the tank to a Tank Pressure Control Valve (small round inline valve) then to the "Tank" port on the Evap canister (they are usually marked)

The other canister port marked "Purge" goes into a Vapor Contol Valve. That Valve has three more ports. One to the carb bowl vent, manifold vacuum and to a Thermal Vacuum Switch.
The last port of the Thermal Vacuum Switch connects to port vacuum from the carburator.

The 4x4 is controlled by vacuum. There is a vacuum switch on the top of your transfer case that control the vacuum to the front axle shift motor. The shift motor has 2 ports, when vacuum is applied to one side the shift motor moves the fork one way and when vacuum is applied to the other side, the fork moves the other way.

The first thing I would do is verify the hoses at the transmission cross member are hooked up. Then I would remove the 4 bolts from the shift motor and remove the motor and start the engine and shift in and out of 4x4 waiting 10 seconds before each shift and see if the fork moves.

If it doesn't you will need to check the vacuum connector on top of the transfer case and make sure it is fully attached, if it is, you will need to remove the vacuum connector and check to see if you have engine vacuum on one port(around 15" vacuum). The ports are as follows - one port goes to engine vacuum, one port goes to a vent and the other two go to your shift motor. The hoses that go to the shift motor are bad for getting plugged, so you should use compressed air and see if they are clear.

If everything checks out, you will have to remove the switch on the transfer case and operate it by hand while the engine is running and see if the plunger moves in and out. Sometimes the plungers will stick in!

A vacuum gauge and pump are needed to check the motor and switch. If you don't have one, you might need to borrow one and put a vacuum on the shift motor and see if it holds vacuum. Once you put a vacuum on the shift motor the fork should move and then should pump down and hold a vacuum, if it doesn't hold vacuum, you will need a shift motor.

This is alot of info, but there are many possibilities for this not working and you will have to check all these things to diagnose this.

if you go to your local autozone, o'reily, or advanced auto and tell them what you need..a ported vaccum switch they will sell you one and most of the time you can take that and look at it and tell were on top the motor it goes.. i have a 1990 3.8 good-luck ray