Climate control causing windows to fog

[Cbierniat]

I figured out why my windows fog up...i thought they did it on their own and the defrost wasnt workin but its whenever i turn anyting on on the climate control it fogs up...and no matter what option its on air is coming out of all the vents....whats wrong...its very hard to drive and now that its cold it sux not being able to use my heat

[GTP Dad]

You have a leaking heater core. It could be just a pinhole but it is causing water to enter the duct work and causes the windows to fog up. The only way to stop the problem will be to replace the core.

[Cbierniat]

alrighty thanks a lot...figures after i dump a grand into it this happens...any idea how much itll run me?

[Cbierniat]

But would the heater core cause it to com eout all of the vents??

[GTP Dad]

Yes, everyone thinks that there are seperate ducts for each but they are all common. The heater core sits in the same duct as the AC evaporator. That is why when you put the defrost on you get the fine water particulates that cause the window to fog. This is a common occurance especially with very small holes that aren't big enough to let a lot of coolant out. It will get worse as time goes by.

[Cbierniat]

OOps .. sorry i worded it wrong i meant no matter what setting the air is on air comes out of all of the vents no matter what(floor defrost & panel)...but the floor is extremely weak almost as if it is not working...would the heater core cause that?

AND it was fine until i had my car worked on and they replaced the following...Oilpump waterpump timing chain & tuneup...do you think they messed something up or it just happened on its own?

[BNaylor]

Originally Posted by Cbierniat

OOps .. sorry i worded it wrong i meant no matter what setting the air is on air comes out of all of the vents no matter what(floor defrost & panel)...but the floor is extremely weak almost as if it is not working...would the heater core cause that?

AND it was fine until i had my car worked on and they replaced the following...Oilpump waterpump timing chain & tuneup...do you think they messed something up or it just happened on its own?

Sounds like something got messed up like the vaccum feed.

Do you have any hot air coming out with temperatures controls in high heat? If only certain vents are working, it sounds like a vacuum problem. Your engine feeds vaccum to the HVAC controls from the intake manifold. If you have a GTP the supercharger has the accessories vacuum connection. I recall without vacuum manual HVAC systems will give you defrost mode only. Without proper vacuum, the digital climate control system may give you vents only, something like that.

[Cbierniat]

the middle panels blow normal..the ones close to the doors barely anythign comes out...but not matter what setting air is coming out of the defrost and panel vents at all times and not really anything on the floor even when its just on the floor its still comin outta everything and yes the air is hot/warm relative to what temperature its set on but whenever i turn anyting on it fogs up

[GTP Dad]

Since you corrected you post, I have to agree with Bob that the vacuum controls have gotten messed up somehow. I would suspect as Bob said the vacuum line is hooked up incorrectly or not at all. Check the lines and once they are correct that should correct the vent issue. The fogging issue will continue however until something is done with the heater core. Also you may want to check to insure the drain is open. Water in the duct work can cause a fogging issue too.

[Cbierniat]

My car hasnt gotten wet in a few days cuz the weather hsa been dry and now the windows havent fogged up but the control over which seettin the air comes out still remains

[Cbierniat]

what lines am i checking and where are they at???

[regalfriend]

I think GTPDAD hit it on the nose...Sounds like a clogged drain....... You should check the cabin filter....see if its wet, and make sure its clean...Im not sure how to check the drain. If it is the heater core, you would lose anti-freeze....Though a small leak from the heater core could cause moisture in the cabin, and may not have a noticable loss in the cooling system....

[BNaylor]

Originally Posted by Cbierniat

what lines am i checking and where are they at???

The vacuum line feeds into the firewall in the area of the blower motor and then branches off to the vaccum actuators, etc. You can undo one and check for suction. It originates at a vaccum line coupler at the supercharger but snakes around the area of the engine compartment fuse box and battery.

Originally Posted by regafriend

I think GTPDAD hit it on the nose...Sounds like a clogged drain....... You should check the cabin filter....see if its wet, and make sure its clean...Im not sure how to check the drain. If it is the heater core, you would lose anti-freeze....Though a small leak from the heater core could cause moisture in the cabin, and may not have a noticable loss in the cooling system....

Regalfriend, '97 - '03 GPs do not come with cabin air filter unless the owner installed one at a later time. If you are comparing a Regal which comes from the factory with one to a Grand Prix that is comparing apples to oranges. A evaporative/heater core clogged drain will not cause his problem.

[Cbierniat]

does anyone hav a picture or anyting? thanks

[BNaylor]

Originally Posted by Cbierniat

does anyone hav a picture or anyting? thanks

Do you have a GTP or GT?

Start in the engine compartment. Below is the map for vacuum on a L67 GTP. The line in question to HVAC is called accessories (ACSRY).



The vaccum line on a L36 SE/GT is off the backside of the intake manifold.

Is your HVAC system manual or the dual climate digital?

I'll post pics of the blower motor area later.