usrjcro11

Sorry for being late updating post. New valve corrected problem.

I will be ordering new valve tomorrow.

will update when I get it in and replaced.

thanks

Well you both are correct. Lines are backwards. I was just hooking to old lowboy trailer whichever way made brakes release. No color codes on trailer.Am I correct by saying no air should come out of either hose without trailer service valve pushed in? If this is correct then is trailer protection my problem with air coming out of trailer line without trailer service valve pushed in?

thanks

I will do some testing tomorrow. Thanks all for replies. Will report back 

4 minutes ago, Joey Mack said:

the red button is not part of this issue Mech..   It is a seperate switch, that only controls the rear air bags..   its actually a simple system, especialy on a 90's truck... 

Correct

5 minutes ago, mechohaulic said:

what you are saying is now when pulling out the red trailer  button, the tractor air bags deflate automatically/

53 minutes ago, mechohaulic said:

going back and forth on your other post about the air lines to trailer.  a "94 is too new for me to know its air schematic.  red button out shouldn't be air coming out trailer emergency line (red) during brake application. between that issue and air bags doing nothing with the switch ;first thought is someone has lines crossed.

Sorry to confuse. Two separate issues.

3 minutes ago, mechohaulic said:

am I correct then the only situation when flipping the toggle was ; you weren't sure what the valve did ?possibly there is nothing wrong with the system . the bags work properly ?

I knew what it was suppose to do but my air bags never purged air to assist uncoupling from trailer.

40 minutes ago, Joey Mack said:

ok....  there is a leveling valve on the front drive axle..  make sure there is a supply of air to it.  if not, let us know..  you can un hook the supply line after you reduce air pressure below 85 psi,  then crank the truck and after 85-90 there should be air coming out of the line you un-hooked.. if not... the regulator at the tank is probably junk...  also, remove the dash panel and see if the switch is an air switch or all electric..  post the results.  jojo

The air bags do not start raising till about 90 psi. Same time as air bag on cab starts raising.

Yes I can tell when bags are inflated after air builds up.

Will test tomorrow. Where should the air exhaust from if switch is working properly? Leveling control valve? Behind dash?

Wondering if I may have a plugged exhaust line. Dirt Dobbers are bad here plugging lines. Had a international truck with vacuum assist brake. Brake pedal hard but no brakes.put new booster on no better. Found exhaust line plugged from dirt dobber. Learn expensive lesson.

I will take pictures tomorrow up and down. Noticeable difference.

Mechohaulic

fully understand. Need all help I can get 

When I flipped switch another person was by fifth wheel and did not hear any air discharging nor saw airbags go down. 

.how long should it take to dump air?  Maybe I did not wait long enough. Should air come out of exhaust port on leveling valve?

There is a leveling valve on front drive axle. I had dash apart looking for air leaks. Truck and trailer air supply buttons have airlines coming into the back of them. No wires 

Yes this 1994 truck has airbags on suspension.

Do not thinks it is because airbags adjust without trailer valve engaged. 

i do have another problems I posted that is separate from this one.

My problem it is not dropping air bags. Am I suppose to do something else after flipping switch? Newbie here my 1991 Mack ch does not have airbags.

Yes raising protected cover and flipping switch up. Sorry for confusion

Raise the cover and toggle up on this 

Unhooked from lowboy trailer today. Discovered air coming out redline when I press brakes without trailer air supply engaged. When  I engage trailer air supply air comes out of blue line for trailer which I understand. Is air supposed to come out of the redline with trailer air supply off? If not what do I need to check?  Thanks

When I lift switch cover and toggle switch up nothing happens. When I toggle switch down a little bit of air discharges behind the dash. How does this switch work. Bought truck about 9 months ago just now trying it. How do I go about troubleshooting? Thanks

Thanks to all that replied. Put Teflon dope on them