defrosting windshield

[trust]

Ive had this issue a while now and cant seem to solve it, when its cold outide, very cold, 20F and below I cant keep the windshield clear, in fact it almost eems as though selecting the defroster makes it worse. Recently in fact it was uncomfortably hot in the cab with the defroster on and we had saucer sized clear spots right at the dashboard level. it wipes clear ok but doesnt stay clear. Ive taken to rainX ing the windows but thats only marginally effective. Whats up and what can I do to fix this before I head back to South Dakota again next week?

Thanks Gurus!

 

[AH64ID]

Is the air blowing out the defroster?

The blend door motors are known to break and you won’t get the air where you want it, which would explain hot on the face but not the windshield.

Feel for air moving from defrost to face to feet and you move the selector. If it doesn’t move check out heater treator.

 

[Timd32]

Yeah you have blend door issues. Hit up YouTube and look up some videos on your year to see if someone has a good trick to troubleshoot yours, could be linkage or the door, or the little actuator controller.

Or get some sort of inverter and a small heater with a blower to rig up and keep the windshield clear till you can get it fixed.

Uncle has an 07 or 06 Lincoln Continental they have that split dual air dual passenger control and a million little blend door actuators, I changed a few and even had to take a few apart because he got the wrong ones but figured out you could swap the little arms and covers. He had no anything forget about just the floor, vent, or defrost just a whole lot of cold and no air anywhere, they must have broke a few at a time over a few years is my guess till he was trying to go from NJ to Pittsburg with no defrost in a snow storm.

How these stupid engineers dont have them fail to defrost or some sort of failure bypass is besides me. I really hate lazy engineers and product managers who dont have a clue how important it actually is to be able to see out your windshield.

There is no reason they should have to be told to do this by some other pencil person in a Govt body, its truly common sense and this is not a Ram, Chrysler, Ford issue I have seen this in Chevy as well my Traverse and a Equinox I have done actuators on, the counter people almost refused to sell me the GM one, they were all about we dont take electrical returns so don't come back if this is not your problem.
Pretty much that Chevy place is out of business again for the 4th time since 2008, no surprise there.

 

[trust]

well I think all th edoors are working if you do the right dance and hold your mouth right, I can get air out of the defroster ducts, feet, dash etc. so I have assumed it wasnt a door issue but maybe it is. I'll take another look while at home vice while driving....

I have a smalle battery powered aux heater/blower but I think its worthless, maybe I can find a better one as you suggest, or a couple of muffin fans sitting on the dash above the defroster ducts... I have those already, hmmmm when in doubt jury rig...

 

[Timd32]

How is the temp of the air, is it the recirculating door that allows cold air in?

So the volume of air seems good just is it always cold?

 

[brucejohnson]

Adding a couple things to look at here:
1. Are all the floorboards dry? If you have a leak the moisture in the cab will be high. Also, I rarely ever turn the setting to recirculate. Always allow fresh air which removes stagnate, humid air and let the heater warm thing up.
2. Is the air conditioner moisture drain working properly and does it have a hose to remove the moisture to a point where it will not drip back through a compromised firewall seal? I have experienced a plugged or improper routing issue on a few vehicle which led to very similar symptoms you are experiencing.

 

[Crunch]

How these stupid engineers dont have them fail to defrost or some sort of failure bypass is besides me. I really hate lazy engineers and product managers who dont have a clue how important it actually is to be able to see out your windshield.

In a sane world this would be grounds for a safety recall. It's not like HVAC door problems are rare or anything...

 

[petersonj]

Ive had this issue a while now and cant seem to solve it, when its cold outide, very cold, 20F and below I cant keep the windshield clear, in fact it almost eems as though selecting the defroster makes it worse.

If there is plenty of air coming from the defroster vents, then I would suspect a small heater core leak. The additional moisture added to the airflow going to the defroster vents will condense on a cold windshield. Has your coolant level been slowly dropping?

- John

 

[brucejohnson]

If there is plenty of air coming from the defroster vents, then I would suspect a small heater core leak. The additional moisture added to the airflow going to the defroster vents will condense on a cold windshield. Has your coolant level been slowly dropping?

- John

I would check the coolant level in the radiator. Often times the location of a small leak will draw air into the system as it cools instead of from the coolant recovery bottle, so you wouldn't notice any indication by a visual check at the bottle.

 

[trust]

Ahhh thanks gents. I'll take a look at the radiator level last I checked it was full as was the overflow bottle but good to double check that to be sure.

I ran a coat hanger up the drain hose yesterday and it appeared to be clear however I didn't get the chance to blow it out with compressed air or even flow a higher volume of water through it.

Floors are dry as near as I can tell except for snow melt coming from shoes. No odor of antifreeze when it blows. If everything seems right i do have a good column of warm air from the defrost ducts but maybe not enough yet

Thanks I'll keep investigating

 

[trust]

I'll go double check the radiator level, I generally keep a close eye but I've been logging a lot of miles lately

I have been getting a good column of warm ai . Enough that my wife complains anyway but maybe I need more yet or it's not what it should be. It is a pain to get the right temp air out of the right vents without some amount of HVAC dance... one of my main complaints about this truck

No water on the floor that I can tell, I do have plastic floor trays but they do end up with snow melt in the so it's hard always to tell. I dont have any antifreeze smell. Pita to change the heater core I assume?

I did try to clean the vent drain yesterday but only a coat hanger clean out I didn't get to compressed air or high volume of water to be sure so that's still on my list to finish. I got nothing out of it from the coat hanger exercise

Thanks gents. Does anyone else have this issue too or just me?

 

[brucejohnson]

I'll go double check the radiator level, I generally keep a close eye but I've been logging a lot of miles lately

I have been getting a good column of warm ai . Enough that my wife complains anyway but maybe I need more yet or it's not what it should be. It is a pain to get the right temp air out of the right vents without some amount of HVAC dance... one of my main complaints about this truck

No water on the floor that I can tell, I do have plastic floor trays but they do end up with snow melt in the so it's hard always to tell. I dont have any antifreeze smell. Pita to change the heater core I assume?

I did try to clean the vent drain yesterday but only a coat hanger clean out I didn't get to compressed air or high volume of water to be sure so that's still on my list to finish. I got nothing out of it from the coat hanger exercise

Thanks gents. Does anyone else have this issue too or just me?

The only times I remember experiencing similar issues was when the t-stat stayed open and only kinda warmed the air, the blend door actuator failed, the AC duct was plugged (heard the sloshing of waves during cornering maneuvers), or big leak somewhere in the cab, or way too much melted snow remaining in the Weather Tech mats.
With all of that sniffing and poking around accomplished I would insure the HVAC doors are indeed functioning to their designed application. Are they properly directing the air proportionally to the selected openings when you make the adjustments?
And under the floormats and under/behind seats all is dry?
Apparently heat is not an issue as the heat detector (wife) has commented the presence of heat.
Good luck in your search.

 

[KATOOM]

The defrost works ONLY if the AC compressor is running. The process of freon expansion in the evaporator absorbs moisture and removes it from the air and then the dry air collects the moisture on the windshield. You can even run the AC with the temp on hot and it will remove moisture from the cab. The air blowing on the windows through the defrost vents is the most effective though.

The few things which can cause poor defrost function is if the AC compressor isnt running, or if the heater core is leaking, or if the HVAC box isnt draining, or if you have excessive moisture in the cab from just soaking wet clothes or a bad leak.

 

[brucejohnson]

The defrost works ONLY if the AC compressor is running. The process of freon expansion in the evaporator absorbs moisture and removes it from the air and then the dry air collects the moisture on the windshield. You can even run the AC with the temp on hot and it will remove moisture from the cab. The air blowing on the windows through the defrost vents is the most effective though.

The few things which can cause poor defrost function is if the AC compressor isnt running, or if the heater core is leaking, or if the HVAC box isnt draining, or if you have excessive moisture in the cab from just soaking wet clothes or a bad leak.

Most certainly. I noticed he mentioned 20 degrees, so I assumed for that moment in time the AC was probably not in function mode, just relying on good old fashioned heat to load up on the humidity and extract it via the normal open circulation process, not in recirc mode.

 

[jhenderson]

I’m betting on a small heater core leak.

 

[trust]

Mmmm thangs gents. The radiator is full full expansion tank is full but I'll keep an eye closely peeled for a core leak.

I did run the compressor for a while but not extensively so I'll do that going forward and see if that helps.

Meanwhile I wired up some muffin fans to augment the blower on the dash

 

[brucejohnson]

Mmmm thangs gents. The radiator is full full expansion tank is full but I'll keep an eye closely peeled for a core leak.

I did run the compressor for a while but not extensively so I'll do that going forward and see if that helps.

Meanwhile I wired up some muffin fans to augment the blower on the dash

I don't know if you can set up some 6x9 co-ax speakers on the dash, or if you have strong dash speakers pointing to the windshield for better entertainment than muffin fans spinning around and around. I had a couple of unanticipated leaks in my 65 Mustang 289 HP back in the era BAC (Before AC); one in the left tail light, seriously moisturizing the trunk to rain forest proportions, and one at the bottom of the right front pillar which had cracked, filling the passenger floorboard under the floor mats. I came out early one the morning to go to work and discovered very, very foggy and iced up interior glass. I thought it was on the outside, but nooo. I started the car and set the controls to full defrost, letting it idle while waiting for the heat to appear and de ice the windshield. In the interim I turned on my Pioneer FM, 4/8 track player and threw in a Deep Purple tape to bide my time. A short few minutes later the windshield was beginning to defrost and I glanced into the rear view mirror to find than two very large oval clearings above the 6x9 co-ax speakers mounted under the package tray were growing rapidly, faster than the windshield. For the next week I found Deep Purple, Led Zeppelin and Black Sabbath to be superior to Dr. Hook, Neil Young, Merrilee Rush (drool ) or Buffalo Springfield in defrosting the rear window when set to almost full volume. Found and fixed the leaks, dry again.
So check closely in all the hidden places for moisture and keep air flow going at all times. Good luck in the search and repair.

 

[Crunch]

Merrilee Rush (drool )

You ain't kidding. Merrilee Rush can clear my windshield any time! She ranks right up there with Melanie Safka in terms of beauty...

 

[brucejohnson]

You ain't kidding. Merrilee Rush can clear my windshield any time! She ranks right up there with Melanie Safka in terms of beauty...

Amen to that brother! Both talented beauties in their own right. Back when people could actually sing more than two notes and play more than one chord.

My neighbor met and hooked up (friendly dating only, so he claimed) with Merrilee Gunst (Rush) for about six months when he went off to college about 63 or 64. He met her at some gig she played on campus. He brought her to his family's house for dinner one afternoon. I was best friends with, and same age as his next younger brother. We were introduced and both of us fell immediately in youthful love with her. She was so light on her feet and so friendly, bubbly, and so darned good lookin'! She noticed an old upright piano off in the corner (seems us country folk all had a piano in the house in those days). She asked if she could play. Jerry (the older brother/date) said, sure, let me chase the cat off of it first. She sat down, smiled, and began some wonderful classical renditions, her brown hair flowing with her rhythmic undulations. Then, without skipping a beat, she morphed into some contemporary songs and began singing. My buddy and I melted; our jaws had to have been solidly planted on the floor, tongues rolled out. This is burned deep into my then young impressionable memory. We even got a quick "puppy hug" and kiss from her when they left after dinner. Eww, cooties! NOT!!!

 

[Jihn]

I have had that twice on different vehicles, both times it was a very small leak in the heater core. I also have it happen in my 08 but only when some warm bodies get in from a moist area like running thru the rain and then jump in the truck, my windshield fogs up really good then. The ac system should remove fog like that in a few minutes. When I put my defroster on the ac automatically comes on, along with fresh air (the recycle option won't work while defrosting).

Try this, take a small hand held mirror and kept it cool, don't warm it up, then when your truck is warmed up and on defrost put the mirror in the air stream for five seconds and see if it fogs up, and if it does it will point at the moisture coming from the heater or drawn in from outside by the heater, I would then do a pressure test on the heater core, and see if it can hold 15 lbs. from a set time. If it can't you will have your answer if it does you will have to look further upstream.

Jihn