92 grand am. defrost works, no heat

[crackedvenom]

defrost barley works, but there is absolutely no heat or air. its getting cold and i really need heat. i was looking on some other forum for a different car and they were mentioning some hose under the hood might be cracked? anyone have any ideas. it would be greatly appreciated! thanks.

[3100]

do you hear blower fan at all?

[crackedvenom]

Originally Posted by 3100

do you hear blower fan at all?

not at all. the only reason i knew the defrost was working because i felt it, i could barely feel it but i mean it still worked. if i kept the defrost on then turned to another setting, it would do a sort of thing, like it was letting pressure out from somewhere.

[3100]

by default when something goes wrong with vacuum lines that control your settings it will always go to default which is your windshield defogger because that is what you need the most. And yes it is letting pressure behind the control panel where your setting knobs are, right behind it you will see bunch of vacuum lines with rubber fittings. Most likely they got disconnected somehow. So remove the center bezel and you would be able to see vacuum lines if not, then try to remove that control panel to get better access behind it. Also on your transmission is a vacuum modulator. This modulator is connected via vacuum lines to your intake manifold, and the same vacuum line splices into a "T" which feeds vacuum to the vacuum lines behind your hvac controls, check it make sure it is in good shape (no cracks etc)

[crackedvenom]

Originally Posted by 3100

by default when something goes wrong with vacuum lines that control your settings it will always go to default which is your windshield defogger because that is what you need the most. And yes it is letting pressure behind the control panel where your setting knobs are, right behind it you will see bunch of vacuum lines with rubber fittings. Most likely they got disconnected somehow. So remove the center bezel and you would be able to see vacuum lines if not, then try to remove that control panel to get better access behind it. Also on your transmission is a vacuum modulator. This modulator is connected via vacuum lines to your intake manifold, and the same vacuum line splices into a "T" which feeds vacuum to the vacuum lines behind your hvac controls, check it make sure it is in good shape (no cracks etc)

thank you, will give this a look tomorrow and see what i can find. will let ya know how it goes

[crackedvenom]

well im gonna get some pics soon but i was busy doing other thigns.

i noticed, as you push the key to start it, just before you hit the a/c part with the key the heat turns on. blows out like theres no tomorrow. once you finally hit the a/c with the key it stops.

ideas now?

[3100]

if the problem is in vacuum lines then you would only get blowing air on top of the dashboard for the windshield. Anyway check the vacuum lines behind the HVAC controls.

[crackedvenom]

Originally Posted by 3100

if the problem is in vacuum lines then you would only get blowing air on top of the dashboard for the windshield. Anyway check the vacuum lines behind the HVAC controls.

edit:::: could this be my issue? http://autorepair.about.com/library/faqs/bl551g.htm


heres a front view of it
http://i37.tinypic.com/10nz7k1.jpg


also a top view.
http://i38.tinypic.com/nccxx.jpg

i pushed all the lines in and they all seem to be working. i dont see any vaccum lines. those are the rubberish ones correct? i found the plastic ones that lead to the heater core and theyre all plugged into where they need to be it seems.

should i go back further or..? maybe this isnt a diy type of problem

[3100]

When did this problem occur? Or did you just buy that car? Check coolant level, check that someone did not bypass leaking heater core (two rubber hoses that are going into the firewall.

[crackedvenom]

Originally Posted by 3100

When did this problem occur? Or did you just buy that car? Check coolant level, check that someone did not bypass leaking heater core (two rubber hoses that are going into the firewall.

well i found a fix after asking a friend today. after starting if i pull the key back just a tad bit, it works fine. im not sure how good of a fix this is since doing this, it turns off the ABS light that usually stays on.

[3100]

Originally Posted by crackedvenom

well i found a fix after asking a friend today. after starting if i pull the key back just a tad bit, it works fine. im not sure how good of a fix this is since doing this, it turns off the ABS light that usually stays on.

that is not going to fix it. It absolutely has nothing to do with the hvac system . That is like saying "I put new brake pads on my car and now my wipers work".

[crackedvenom]

Originally Posted by 3100

that is not going to fix it. It absolutely has nothing to do with the hvac system . That is like saying "I put new brake pads on my car and now my wipers work".

lol, well any ideas for me to check out? got the next couple days off so i can mess with it

[3100]

sure I will try to help you but first I have to know more details and try to be as precise as possible. Also do all the cheks that I tell you if you skip them then I will asume that something is OK. when it is not.

do you know where the heater core box is?
If you drive the car for half hour or more and engine temperature gets to normal operating temperature then you should have some heat. You can try to touch the black plastic housing for your heater core it should feel warm if not and engine is warm then most likely someone bypassed the leaking heater core with some small pipe. Heater cores can also be clogged, you can check this by touching inlet pipe it should be hot and if outlet pipe is not warm then you know that the heater core is blocked inside. Also the big fan in front of the radiator is not the lower fan that I was referring to in my previous post. If you can feel air blowing at certain settings and at other setting you get nothing, that can mean that you have blower fan resistor issue.

so tell me what are the temperatures of the inlet and outlet heater core pipes that run into the firewall after the car has been driven for 30min or more. Then tell me at what settings you get air and where and at what settings you get nothing.

example: air is blowing at speed 1 and 2 or low and mid but not at hi etc....

give me more details.

[crackedvenom]

yes it has heat. i took out the heater core cover screws and it seems to work a lot more now. still stops working sometimes. ill check the other stuff in a day or two. been busy