If I move the lever to hot inside the car and have defroster going, no heat gets into car. On cold days, window fogs up and I have to keep wiping it. WTF! What could be the problem and how do I fix it. It is so annoying. Searching didn't bring up anything unless I'm using the wrong words. HELP! Thanks in advance.

 

check to see that the hot/cold door is actually moving with the switch. My old IROC the where the cable connects under the pass. side of the dash to actually move the door had broken off. Only way to change it was to crawl under and use a pair of pliers.

 

Cool! I'll check that out but if it is broken, is there a replacement part or am I going to have to go junkyard digging? What other things could it possibly be?

 

radiator full? Any air in the coolant lines? is it really fog, or could you be getting coolant on the windshield (bad heater core)?

 

Coolant is full. It is fog on the windshield and not coolant because you can wipe it away with you sleeve and it will go away for a while. I've been searching and fould out about the vacuum lines and if there's a leak, that could be the problem but where do these lines go under the hood. They have to get vacuum from somewhere. Thanks.

 

If it's a bad heater core (slightly leaking) causing the humid vapours off the coolant to fog your windshield, there should be a fairly nasty sweet pugnant odour. Is this happening?
In these cases you should generally still have some heat as the hot coolant passes through the heater core, unless it's plugged and just weeping enough coolant to cause the slight leak.

Or is the source of the fogging coming from you (breathing, a coffee, wet hair, etc), and then unable to remove because there is no heat?
If that's the case, then check the control connections as Jay pointed out, and also make sure the coolant level is OK and it's circulating through the heater core hoses under the hood.
An easy way to check that is to just wait until the car is up to temperature. Then when your trying to use heat the interior, feel with your hands on hoses that run to (and from) your heater core. They should both be hot to the touch. If they are cold, then there is a problem with the circulation (a possible blockage or air). If they are hot, then there is likely a problem with the heater control.

Good luck.

 

Thanks, I'll check it out and let you guys know what happens. The fog isn't sweet but watery. The fog is from my girlfriend and I breathing so heavy. Don't ask why.

 

Why?

 

Uh, because there isn't much a woman won't do in the passenger seat of a third gen F-body. I take advantage of this all the time. J/K. No, on a serious note, my girl and I fell asleep in the car and when we woke up, all the windows were fogged up. That's cool but I need to be able to unfog them.
P.S. Don't act like you haven't taken advantage of the fact that you drive a third gen and don't act like you haven't gotten some female attention because of it because if you say that, I'll call

 

also check to see if te vac line that is in your engine bay is hooked up. it will go from the heater valve on the pass side to the harness that goes into the firewall next to the dist.

 

MY BUDDY HAD THIS PROBLEM ON HIS VET. HE REPACED everything BIT THE HOSES. COME TO FIND OUT THERE WAS A CHECK VALVE IN THE HOSE. CHECK FOR IT IT MIGHT BE CLOGGED. WHY ITS THERE IDONT KNOW. BUT IT FIXED IT AND IT WAS ODVIOUS WHEN YOU PUT YOUR HAND ON THE HOSE AFTER IT WAS DRIVEN FOR ABOUT 20 MIN. HALF THE HOSE WOULD BE COLD

 

No, there are no "check valves" in any of the hoses.

 

http://www.ecklers.com/product.asp?p...dept%5Fid=1193


HAHAHA I LOVE PROVING PEOPLE WRONG
THIS MAY NOT BE YOUR PROBLEM BUT JUST CHECK IT
THERS ALSO A FEW OTHER THINGS ON THE RIGHT ON THE LINK I GAVE YOU
IT SHOULD BE THE SAME FOR CAMARO FIREBIRD ECT......

 

Corvette Hot Water Control Valve, 1992-1996

• [*]
• [*]
• [*]
• [*]

This stock replacement hot water control valve is manufactured by GM or by one of its authorized suppliers for use as a factory replacement part. You will find the fit, finish and function meets all GM specifications. Using stock replacement parts from Eckler's, such as this hot water control valve, is a sound investment in the restoration or repair of your Corvette.

Item# 39378 In Stock - Low Quantity
$12.99 ea.

 

Yes, lovely. If only he had a Corvette then he'd have something to put that in.

There are no check valves in any of his hoses.

 

good luck with it, ill be back on here to see if he finds one

 

Ha most girls laugh and say.....i aint riding in that m ullet mobile, besides they have practicly no back seat and a damn center console......

 

you talked about vac lines might be the prob wit heater controls..i havent checked to see if my hoses are hot or not but i removed the heater regulator valve and just tied all the lines together. i remember NOT plugging the vac line the runs into the dash from the firewall..could this be why i have no heat? do i NEED to have vaccum to that line in order to have heat?

 

You need vacuum to that line to control the vents.

 

do ya think i have heat circulating through those lines? if not im just gona run the intake water to the inlet of heater core, outlet of heater core to radiator, cap of 3rd line

 

If you've bypassed the heater control valve properly than you should have heat through it. You should be able to feel the hoses and tell.

 

ok i;ll check that in a few minutes...where would i run vaccum to that vac line? i have the vac line on the front of the tbi plugged from the ultimate mods ..could i route that for the time being?

 

Run it back to wherever it came from stock.

 

it ran to the heater regulator valve. which is gone. theres one small vaccum line coming out of a branch of the wire harness that ran from the heater controls to the heater regulator valve. that broke. is this the one we are talking bout? what do i do here

 

I'd have to look at a vacuum routing diagram for the car. You can connect it to any source of manifold vacuum and it should work fine.

 

do you know that port on the tbi im talkin about? <serious quesion not tryin to sound arrogant or an aZZ or anything. will that suffice as a vaccum to hook to the line?

 

No, not offhand without having to look at a diagram. If it has manifold vacuum on it (you can feel it on your finger at idle), then it should work.

 

ok i'll check it out.its whatever line the tbi ultimate mods suggests plugging..i dont remember but i beleive it ran to the stock air cleaner assembly.

 

It sounds like that would originally have been the vacuum line for the Thermac valve, which there wouldn't have been much point in plugging. I don't know though, I'm not familiar with the ultimate TBI mods.

 

hmmmm i have the same problem.

i did the heater control valve delete that i read about on here, it did look alot cleaner and i wanted to complement my valve covers since i did a 305-350 swap.( everybody else who did this still had heat so i sed why not)

before the heat use to work . and then my heater core went and it started leaking. so i replaced it and i only get luke warm air,

another thing i think that im not getting full air like if something is blocking the air i feel alot of the air come from the heater core department. could it be the latch that some one else mentioned earlier?

 

Which latch is that?

 

ok so here is what i have put together. the vac line was broken off too far into the harness so i said *** it and tear into the dash. i took apart the dash on drivers side and located a vac can that when "pressurized" or vaccumed it opens up a sort of door a plastic door. this only happens when using the a/c selection on the panel, i dont even have a/c but the controls are still there. now, when i switch to heat, the doors close, im assuming because of the vaccum leak isnt allowing the vaccum canister to hold vaccum stopping the magic door from opening. so i turned it all on a/c and while the door was open i bungie corded the arm that opens the door so it stays open..now all i can do is wait till cold morning and see if that will give me heat. whatcha think?

 

bump

 

I'm at a bit of a loss, I haven't poked around behind the dash of an A/C car. I might have to get the book out and see how it works.

 

their is some sort of latch their by the feet of the passenger it sits behind the center council ........and when i put the heat on or the ac all the air for some reason comes out of their like if their some sort of blockage and the air is coming out where ever it can.

keep in mind i still only get luke warm air.
and the hell with the ac im taking that out anyway

 

You might have a vacuum problem that's keeping your vent controls from operating.

 

yea that would suck big time any advice im tryna get this figured out before the new york winter hits

 

The vent controls in my car are working, they switch to the position I want them to. The door for cold and warm air has got to be working because you can hear it and it sounds like there is even a pressure difference between the settings. My concern is that the hoses under the hood that go to the firewall are not warm. What do I do from here? Thanks for any help cause yesterday it was 60 in the morning and this morning was 52. I need heat. Thanks!

 

Oh, and uh, thanks quickchicken. I needed a response like that because with the way you discribed it, even my 7 year old niece could find that vacuum line! You got a way with words!

 

all4u sounds like your heater reguator valve isnt working correctly. your right about the blockage i just dont think your looking in the right direction. sounds like your valve is bypassing all water back to the radiator instead of directing it through the heater core first..so, it could be a bad valve, or a vaccum problem, or both. i would start by heading to the scrap yard and locating another valve replace the one you got being VERY CAREFUL not to break your vaccum line as its very old and stiff and brittle. also, make sure you dont snap any of the "nipples" off of the valve. if your lines dont get heat then, you have a vaccum problem or a control problem....now for me..operation bungie was a complete failure, seemed to blow semi luke warm air for about 2 minutes and then back to cold air..im at a loss of ideas besides replacing it all which is costly and very time consuming so..any suggetions apeiron?

 

If you suspect that the bypass valve has failed, you could just eliminate it.

 

Bypass? What does it look like? Can someone take pictures of everything I'm supposed to be looking for? I know it's alot to ask but I'm begging you. It's getting cold outside. Please help!

 

What year and model is your car, and what engine does it have?

 

this is it

 

yea i took minds off looks alot cleaner now. but the heater core is always running

 

Not all years used the bypass valve, so don't be too alarmed if you don't have one.

 

true .....
on my 85 it didnt have one but it had a hose go directly to the water pump

 

so anybody figure out the vaccum of these things yet?

 

Well, I felt the heater hoses and there is no coolant in them. One goes directly to the radiator and the other one goes down under the back of the engine somewhere. The one that goes to to the radiator goes to a junction with another hoses made of metal. It looks like a metal line from the radiator that heads off some where by the firewall and then it has this orange hose that heads up from the metal line and this hose goes to the firewall. The hoses next to it, the other heater hose, I'm having a hard time following. What should I do now? How is the best way to bleed the system?

 

I bled the system according to shop key and I also noticed I can't find that heater control valve. After my brother looked at it, he said that's because I don't have one. He told me it would be behind the A/C compressor and it isn't there. So now, is there someway I can super $#!T rig the hoses to the heater core and get heat without F-ing anything up? Thanks cause I'm baffled!