If you can leave the black line hooked up, then feel for vacuum on the other ports, you should be able to use the logic chart to determine if your control head is working properly. If it is not, then the first thing I would do is replace the head.

 

Well when I leave it hooked up all I can hear is the vacuum leak of the black line trying to suck in,....as i change the switch from any position...nothing changes...the only vacuum is the black line..

 

If, with only the black line hooked up, you do not get vacuum on any of the proper ports (as defined by the pictures in the post I linked to above), then you have an internal fault in the control head.

 

There is a vacuum cluster that plugs into the position switch...no matter what position the switch is in, there is suction only coming from the black line...there is no air being sucked in OR out of any other lines in this cluster other than the black...when i turn the switch to floor, defrost, vent, ac, nothing changes....when i plug in that cluster of vacuum lines, nothing changes...just get the hissing sound

 

Ok... I think I see what the problem is here... I didn't think I needed to spell it out like this, but...

You need to keep the black line connected to the back of the HVAC control head, everything else gets disconnected. The black line is the supply line from the engine to the control head. If you have to make up a short piece of vacuum hose to keep it connected, do so...

Then use the logic chart to see if the ports have 'vac' when they are supposed to depending on the mode you have the hvac control module set to. You will then start the truck and check for vacuum per the logic chart. If nothing gets vacuum, replace the control head as I have instructed as there is an internal failure of the valve inside the head.

If, while you are checking this, when you cover the proper vacuum ports (that state VAC on the logic chart for the selected mode) with your fingers, and the hissing sound stops, then you either have a broken line or a failed actuator which will require further trouble shooting (more jumper hoses, etc).

I recommend that you print out the vacuum routing diagram and the logic chart for easy reference while you are performing this diagnosis.

 

Thanks kyle..I just replaced the control head and that was the problem...I also have SES light on...It's the P1153 H02S Insufficent Switching Bank 2 Sensor 1. Which oxygen sensor is this?

 

Glad you got it fixed.

B2S1 is the upstream sensor on the passenger side. This sensor will be directly ahead of the 'Y' in the y-pipe. Before you go replacing the sensor, I would swap it side to side and see if the code follows the sensor. If it does, replace the sensor. If it doesn't, then you have another issue.

If you decide to replace the sensor (either now or later), do yourself a favor and get the genuine AC Delco sensors. I have messed with a lot of aftermarket sensors and none of them have had the out of the box activity that an AC Delco sensor has. Activity is directly related to the life you can expect out of the sensor. All of my experience and testing has been on GM vehicles.

 

So the one closest to the motor on the passenger side. Am I correct?

 

yes, you are correct. It is the sensor closest to the engine on the passenger side.

 

There are kits available to ream out the valve body and install new TCC isolator and regulator valves... CLICK HERE

ok, I found this link you posted and I couldn't get it to work...where can I find them and are they hard to do?...I am also having some 1st to 2nd shift problem...it is just very rough or hard..... but no codes...had a flush done a few months back...