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GMC Safari/Chevy Astro Heating / Cooling



  • vp79vp79 Posts: 1
    I found a break in my hose coming off the condenser. The problem I am now having is that the end of the hose disconnected from the intake area/ place near altenator and I am not sure where to look to put it back. Can you tell me the specific area I need to look or what it is I am looking for?
  • Hope you fixed it but if you didn't.... The problem may be in two places. The first and easiet is the manifold located on the left side facing the engine. It is located to the right of the black box. One line goes through the firewall, one goes down, and one goes across the top of the engine. In my case, mine was badly worn on the down part and the one going across the engine. There should be no problem fixing the one next to the black box. The other one is an issue if you don't know where it is. There are two ways to get to it.

    If you know how to remove the engine cover, you'll have better access to the manifold. The manifold is right on top of the valve cover. If it is broken off, it's a little tough to see it. Just keep looking for a black vaccume that has one hose coming from the valve cover about 1/2" into the unit. The other side has the fitting. Be very careful taking off the hose, you don't want to break off that fitting. I took the fitting off and cleaned out the broken part. I then used a small piece of hard tubbing and joined it with the tubing I bought at the auto store. I bought about 6" more then I needed so I could move the line away from the heat.

    The other way. If you can reach the air cleaner screw, remove the air cleaner assembly. Look for the aluminum tube running in front of the vlave cover. Right behind that you'll see the vaccume. The line has a right angle on it. If you can pop off the vaccume line, you will be able to repair the line. I used a section of the hard vaccume line as a coupler. it worked just fine. I hope this helps. I know I had a difficult time becuse I did not know where the vaccume was located. Once I found it, It took about 10 minutes to fix it. The car is blowing through all vents in all settings.

    One other note. I did have to change out the resistor located in the blower housing. The number one plug was burned up. I figured the vaccume line failed which caused the resistor to overheat. That was a $65 part. Not to difficult to change and located behind the wiper and coolent tanks. Just pry the plastic plugs up from the top. You'll see a small groove. The black plug comes all the way out and just lift out the tanks after making a few disconnections. Remove the two screws holding the hoses, then the two screws holding the resistor. You just have to disconnect the wire on the left. It resistor will comes right out after taking off the two screws.
  • Hi Gang,
    I've searched all the threads..seen some reference to rear heater not blowing hot....but found no solutions.
    Rear heater and AC blowers\speeds work fine, heater does not blow hot and AC does not blow cold. Front heat is all good on speeds and functions, etc.
    Any suggestions on how to troubleshoot and fix rear heat problem would be appreciated.

  • Hey did you ever figure out the vacuum line and were it goes. I have the exact same problem and I can't find were it goes to save my life. I had the inside engine cover off, the air intake off and the throttle body cover off, still can't find were it plugs into. The hard plastic vacumm lines that go from the A/C and over to the valve cover are all fine. It's that same soft rubber hose that was just dangling there and dry rotted as dry rotted can be. it's about 14 inches long. I've been to a hundred web sites and they all refer to the hard plastic lines...gahh it's frustrating as I'm a pretty good back yard mechanic
  • Hi all,

    I have a 96 chevy astro van that has a climate control without a/c. The interior knob broke off
    so I went and got a replacement controller, but it also has an a/c turn on it. I got it installed but
    it is not working. Do I have to get a climate control without the ac attachment or should it still work. Any advice would be great. Going to take apart and give it another shot. Thanks
  • Hi,
    I posted a query back in November about the rear heater blowing air fine on all speeds, but the air is cold. I flushed the rear heater core, but still just cold air. Would there be a vacuum-controlled valve that regulates the ratio of hot coolant to the rear core somewhere?? Any info or ideas would be greatly appreciated.

  • Well, I managed a temporary fix for my own problem and thought I would share it, in case others have the same problem. Just to the right of the black heater box , below the silver AC condenser/drier you will find a solenoid with upper and lower 5/32 vacuum hoses. The upper one comes from the firewall, the lower one goes to the valve that controls hot coolant to the rear heater core. Apparently the solenoid stuck closed last summer due to lack of use.
    So I disconnected the two hoses and connected them directly with a 90 degree 5/32 connector. I now have hot coolant going to the rear heater core all the time which can be regulated with the rear heater fan switch. Van is a 97 GMC Safari AWD, but I believe this would work for all model years.

  • 2000dcastro2000dcastro Posts: 1
    edited February 2012
    Can anyone tell me how to get to the heater core on a 2000 astro van, please. I have a coolant leak under the passenger dashboard and that seems the logical problem.
  • I have a 91 Safari, and it's just a matter of a few screws to take out on the plastic dashing on the passenger side.. should be pretty simle to get to.
  • Did you ever get this figured out? I have the exact same problem in my 91' Safari?
  • Replaced the thermostat, bypassed the stupid heater control valve with Stainless steal tubing and flushed the heater core with water while I had the HCV off. Still only luke warm air.. what else could it be?
  • sortofsortof Posts: 3
    replaced the vacuum lines coming from the vacuum reservoir at and to the passenger side front wheel to the firewall,so now I'm getting air both hot and cold every were except hot air to the floor, where I need it most in the winter :confuse: any clue or solution's would be helpful, Steve
  • rwidelocrwideloc Posts: 1
    Can someone kindly send my the vacuum diagram being discussed. The A/C on my 01 Astro shuts off will climbing hills and now does not blow hard enough though it is coming out cool.
    My email is

  • tolitstolits Posts: 2
    can you please send me the diagram of the vacuum hose rear terminal on my 2000 gmc safari. please email me at
  • tolitstolits Posts: 2
    I have the same problem can you please e mail me the instruction on how to fix it it and the diagram as well. Thank you so much. My email add
  • edthomasedthomas Posts: 3
    I have the same problem with the heater/AC vents (2002 Safari AWD cargo van) - I've replaced the 5/32" hoses to the vacuum canister and from the firewall to the small 'T' valve, and have inspected the smaller hose that goes to the throttle body/PCV valve and it looks okay.

    A vacuum hose diagram would be most helpful!

  • bdarbdar Posts: 19
    Hi Everyone,

    Have been away from the Forum for a while and I do apologize for not being able to help everyone. Have created a link on my site with all the Chevy Astro Vacuum Line Info and Vacuum Diagram. Do check it out and feel free to email me at if you have any questions.

    Take Care,

    Basem D.
  • kdowneykdowney Posts: 6
    Did anyone get this diagram we've all been looking for?
  • edthomasedthomas Posts: 3
    Thanks Basem! That's a big help, but there's no legend to identify what the numbers on the diagram indicate - is there perhaps another page with that info??

    Thanks again,
  • Problem solved! I decided to disconnect the ends of the small vacuum tube that runs from the 'T' valve on the passenger side in the engine compartment back to the throttle body (thin black tube with 'L' shaped fittings on each end). The intent was to blow through it to see if it was plugged, and if not, plug one end and blow again to check for leaks.

    Well, when I pulled the fitting off the throttle body, the small tube disintegrated in my hand! So, I got a piece of 5/32" vacuum hose and replaced the small one with that, and now have functional AC/heat controls!
  • kdowneykdowney Posts: 6
    Awsome. I just did the exact same thing and have much more air blowing on all settings. I may even have heat now, but won't really know until it gets cold out :confuse:
    Replaced a couple other ones that were looking shabby as well while I was in there.. :shades:
  • old_fogeyold_fogey Posts: 1
    edited November 2012
    I have found my broken vacuum line (L shaped ends) under the hood. Is the end that has to be connected to the intake manifold located on the left, or right side
    of the engine when viewed from the front of the car.
  • Its located on the right side of engine. I accessed mine from inside vehicle.
  • I too found this hose. I think it ran from my firewall to the EGR valve or something. Either way it was practically disintegrated. Now I have SOME heat. Still not perfect.. :confuse:
  • I have a 99 safari van i have replaced the water pump and thermostat and the motor dose not heat up to put heat out the heater in side unless u drive it about 10 miles or more can any one help with this
  • I have a 99 safari van i have replaced the water pump and thermostat and the motor dose not heat up to put heat out the heater in side unless u drive it about 10 miles or more can any one help with this
  • I too have this same problem !! 95 astro van I have replaced the thermostat! The dealer that I WENT TO ONLY SELLS THE FACTORY RECOMMENDED 90 DEG. so I bough a 170 deg. at auto zone thinking of taking a trip across the desert and wanting a lower operating temperature doing so and the motor still dose not heat up to put heat out the heater in side unless u drive it about 10 miles or more ??/ so if you resolve this before I do ??/ sent some feed back as to the problem??/ and I well do the same !! Steve
  • There is little to no heat on the front heater. Rear heater works fine. What do I got to do to fix this?
  • ptolleyptolley Posts: 1
    Thanks for the detailed description of the vacuum line repair to my chevy astro!! the repair took me about 20 minutes including the autozone stop. Thanks again!!
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