The Manuel calls these comfort controls. It is the switch that select where the heat goes floor or both or just defroster or in your face . it is under the switch for blower motor.



Anyways it will not switch to the different selections heat goes to the floor and to the defroster. How can I see if this is the switch OR vacuum problem? (I have looked for vacuum diagram)




I am hoping this is a vacuum problem and is causing my 4x4 not to work as well..... I have 96 blazer 3 button 4x4, light on switch comes on and I hear the noise engaging something in the front but they don't seem to work.

2 different problems I know but any ideas will be grateful.Thanks I will still tri to fine the vacuum diagram thoe





I am going through alldata diagrams but just do nt have an easy to read diagram of the vacuum hoses for the switch that send the heat or ac to the floor/in the face/windshild.

Please help.

 

no takers or thoughts

 

I can only reiterate what every thread on this topic already states (and what you would have found through searching and reading)... You have a vacuum problem. Start with checking for vacuum at the back of the hvac panel in the dash. If you do not have engine vacuum there, move under the hood and start tracing the lines from the intake manifold (near where the PCV line ties in) to the check valve, then to the 'T's, firewall, transfer case, and vacuum ball.

And yes, your hvac & 4wd issues are very likely to be resulting from the same problem.

 

Thank you,

I really did search my as@ of on this..

I just needed some confirmation on the possibility of both systems being related with a vacuum problem.

I don't know how involved under the dash area will be and it is cold here is Wisconsin at the moment like 17 degrees ... BRRRRR

What would be your best suggestion (and the quickest due to the cold) of getting to "hvac panel in the dash" ??

Thank you

 

To "Get to" the HVAC panel, you need to pull the drivers side hush panel (2 screws) down a little. After that is lowered enough you will see two screws holding the gauge surround on. Then look into the gauge cluster and up at the dash. There is one screw there. Then gently start pulling the gauge surround out (around the radio and HVAC panel is held on with clips) Be careful of the wiring for the 4x4, rear wiper and headlamp switches. You will need to unclip the wiring for at least the 4x4 and rear wiper. Then remove the two screws for the HVAC panel. Then grab hold of all four release tabs on the panel and pull out.

 

Thank you , but whats a "hush panel" and yes I googled it LOL

going down to look now thoe..

 

its the panel that meets the gauge surround at the steering column level.

 

Thank you

 

swartlkk and stlwaco Thank you so much..


I started looking at thos vacuum lines from the vacuum ball mounted on the hood. I saw the hose going to PCV valve was dry rotted and had a 2 inch crack in it. So I replaced all 3 hoses. And it worked.

NOTES::

However I notice that driving in 4wd thr front tires are fighting one another and a loud roar from the front. I am going to remove the battery and check the diaphragm and the cable for operation.


There is vacuum to the diaphragm, with the engine running My friend hit the 4x4 button to 4hi and I saw the diaphragm pull the cable out. On snow the 4x4 seems to work but when I hit dryer payment the truck want to pull to the left (this is the side in 4dw that turned). I believe the passenger side is not
engaging. I am still reading this tread [url]https://blazerforum.com/forum/showthread.php?t=7180[/ur
================================================== ================================================== =======================================
This diaphragm does it engage the right wheel ???
the t-case is locked in 4x4 mode confirmed


I noticed the front tires are 235-75-15 and the Passenger rear is 235-75-15 BUT the drivers rear is 235-70-15..... will this cause the passenger side front not to engage when the drivers side is ??

?????????????????????????????????????????????????? ?????????????????????????????????????????????????? ?????????????????????????????????????????????????? ???????????????????????????????????


Thanks so much...