check valve question

[baxsom]

i have been trying to troubleshoot a non operating wiper door. i have the troubleshooting manual from mid america but it doesnt talk about the check valve right after the filter on the manifold.

when the car is warm i get 17 inches right after the filter. then on the large hose after the check valve i get 17 but the small hose on the check valve i get nothing.

is that normal or should i get a reading from both hoses coming out of the check valve.

thanks

 

[wishuwerehere82]

You should get the same vacuum level on both ports coming out of the check valve. Here's why.
The large line goes to the accumulator can the holds a volume of low presure air(Vacuum) to operate the headlight actuators.
The small line goes to the headlight switch and the manual override switch and wiper switch. After that the respective vacuum lines go to your wiper door actuator and the headlight actuator vacuum relays.
Without the small line working, there won't be any vacuum to activate the relays that power the actuators.

 

[baxsom]

so that fact that i only get vacuum out of one port is a bad thing.
i guess i should order another valve.

both headlights work great though, does that mean anything?

 

[wishuwerehere82]

Truely a bad thing, but a cheap fix for about $14.00.
Are you just putting a vacuum gauge on the fitting to read it? Or are you using a "T" fitting to monitor it in use in the system?
If using a "T" inline it could indicate a broken hose up in the dashboard, or a broken fitting off one of the valves.

 

[baxsom]

i was just starting the troubleshooting.

i put a vacuum gauge before the check valve straight to the manifold.
then plugged the check valve back in and started checking the vacuum on each of the ports of it. i was plugging my vacuum gauge straight into valve to start with.

so far i have gotten my headlights fixed and the override in the dash works for them.

i know that the actuator for the wiper door works because if you blow into the hose going to it the doors go up and if you have them up with the motor running they go down.

so after reading my troubleshooting manual that (to me anyway) says that there is a problem with the control circuit which i believe is that small hose on the check valve.