# 2004 duramax moisture in cab



## rich414 (Jan 4, 2010)

Guys, in a 2004 duramaz 4x where is the fresh air intake for the cab located? i want to block this off to see if this stops the moisture issue. When the snow builds up on the windshield, under the wipers the moisture increases in the cab to the point there is water on the inside of the cab. I remove the snow buildup, tried driving with the windows cracked, the A/C will not work in cold weather, tried recirc air, not fresh, looked on GMpartsonline to try and figure this out and there parts diagrams are poor at best, but no real details. any suggestions are appreciated!! happy new years!!


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## BUFF (Dec 24, 2009)

Has this been an issue all along or something new?
If it's something new did you happen to have a new windshield installed recently?


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## EWSplow (Dec 4, 2012)

rich414 said:


> Guys, in a 2004 duramaz 4x where is the fresh air intake for the cab located? i want to block this off to see if this stops the moisture issue. When the snow builds up on the windshield, under the wipers the moisture increases in the cab to the point there is water on the inside of the cab. I remove the snow buildup, tried driving with the windows cracked, the A/C will not work in cold weather, tried recirc air, not fresh, looked on GMpartsonline to try and figure this out and there parts diagrams are poor at best, but no real details. any suggestions are appreciated!! happy new years!!


Maybe I'm wrong (not the 1sttime) , but shouldn't the ac run when on defrost?


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## SilverPine (Dec 7, 2018)

EWSplow said:


> Maybe I'm wrong (not the 1sttime) , but shouldn't the ac run when on defrost?


Yes, they AC clutch cycles on defrost.



rich414 said:


> Guys, in a 2004 duramaz 4x where is the fresh air intake for the cab located? i want to block this off to see if this stops the moisture issue. When the snow builds up on the windshield, under the wipers the moisture increases in the cab to the point there is water on the inside of the cab. I remove the snow buildup, tried driving with the windows cracked, the A/C will not work in cold weather, tried recirc air, not fresh, looked on GMpartsonline to try and figure this out and there parts diagrams are poor at best, but no real details. any suggestions are appreciated!! happy new years!!


Is this a single cab? I have an 03 and used to have an 05, they both had moisture build up. 
Extended cab 05 was fine, no moisture. I always assumed it had something to do with how it was insulated as well as the interior space.


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## rich414 (Jan 4, 2010)

rich414 said:


> Guys, in a 2004 duramaz 4x where is the fresh air intake for the cab located? i want to block this off to see if this stops the moisture issue. When the snow builds up on the windshield, under the wipers the moisture increases in the cab to the point there is water on the inside of the cab. I remove the snow buildup, tried driving with the windows cracked, the A/C will not work in cold weather, tried recirc air, not fresh, looked on GMpartsonline to try and figure this out and there parts diagrams are poor at best, but no real details. any suggestions are appreciated!! happy new years!!


 UPDATE TO YOUR QUESTIONS, THIS HAS ALWAYS HAPPENED WHEN PLOWING FLUFFY SNOW AND THE SNOW PILE ON THE CLOWING BETWEEN THE WINDSHIELD AND HOOD. THE PLOW HAS A HOME MADE CONVEYOR MAT THINGIE TO KEEP THE SNOW FROM BLOWING OVER, BUT ITS A V PLOW AND THERE IS NO PROTECTION IN THE MIDDLE AND THAT' IS WHERE THE SNOW IS COMING FROM. ORDERING A "REAL" DEFLECTOR THINGIE NOW LOCAL GM DEALER SAID WHEN IN DEFROST THE A/C WILL "NOT" WORK WHEN 15 DEGREES OUTSIDE. THIS IS A DOUBLE CAB. THE WINDSHIELD IS STOCK. SO THIS IS WHAT I JUST DID, I TOOK THE WIPERS OFF, AND THE CLOWING OFF, AND TAPED OFF THE FRESH AIR INTAKE. THEN WENT PLOWING WITHIN 15MIN I WAS WIPING THE CONDENSATION OFF THE INSIDE, TIRED THE DEFROST WITH AC. NOPE. LOWERED ALL 4 WINDOWS- JUST FILLED THE TRUCK WITH SNOW. TIRED HEAT- NOPE. PARKED THE TRUCK IN THE BARN 65 DEGREES OPENED ALL 4 DOORS, WITHIN 20 MIN MOISTURE WAS GONE. SO THE TAPE TRICK WAS A WAIST OF TIME. ALSO THERE IS NO SMELL OF ANTIFREEZE AND THERE IS NO MOISTURE ON THE PASSENGERS SIDE CARPET


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## rich414 (Jan 4, 2010)

rich414 said:


> UPDATE TO YOUR QUESTIONS, THIS HAS ALWAYS HAPPENED WHEN PLOWING FLUFFY SNOW AND THE SNOW PILE ON THE CLOWING BETWEEN THE WINDSHIELD AND HOOD. THE PLOW HAS A HOME MADE CONVEYOR MAT THINGIE TO KEEP THE SNOW FROM BLOWING OVER, BUT ITS A V PLOW AND THERE IS NO PROTECTION IN THE MIDDLE AND THAT' IS WHERE THE SNOW IS COMING FROM. ORDERING A "REAL" DEFLECTOR THINGIE NOW LOCAL GM DEALER SAID WHEN IN DEFROST THE A/C WILL "NOT" WORK WHEN 15 DEGREES OUTSIDE. THIS IS A DOUBLE CAB. THE WINDSHIELD IS STOCK. SO THIS IS WHAT I JUST DID, I TOOK THE WIPERS OFF, AND THE CLOWING OFF, AND TAPED OFF THE FRESH AIR INTAKE. THEN WENT PLOWING WITHIN 15MIN I WAS WIPING THE CONDENSATION OFF THE INSIDE, TIRED THE DEFROST WITH AC. NOPE. LOWERED ALL 4 WINDOWS- JUST FILLED THE TRUCK WITH SNOW. TIRED HEAT- NOPE. PARKED THE TRUCK IN THE BARN 65 DEGREES OPENED ALL 4 DOORS, WITHIN 20 MIN MOISTURE WAS GONE. SO THE TAPE TRICK WAS A WAIST OF TIME.


ALSO THERE IS NO SMELL OF ANTIFREEZE AND THERE IS NO MOISTURE ON THE PASSENGERS SIDE CARPET


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## Mebes (Feb 7, 2004)

If your cab is humid you need more fresh air not less.
Fresh air is dry, recirculated air is full of moisture from the snow melting off your jacket boots etc. You need to get that humid air out.

If your cowling near the wiper area packs full of snow it is blocking the fresh air intake. You need to address that problem first.

Clear it off and run the blower on high with only 1 window completely down to minimize the snow getting into your cab.


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## rich414 (Jan 4, 2010)

Mebes said:


> If your cab is humid you need more fresh air not less.
> Fresh air is dry, recirculated air is full of moisture from the snow melting off your jacket boots etc. You need to get that humid air out.
> 
> If your cowling near the wiper area packs full of snow it is blocking the fresh air intake. You need to address that problem first.
> ...


Agreed on the cowling packing with snow, stops the fresh air and fresh air is DRY recycles air is WET. i am plowing a 4 mile subdv road, so whats your suggestion to keeping the snow out of the cowling area? when the snow is not packing up there is NO moisture issue.


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## Randall Ave (Oct 29, 2014)

I do roads, have a ford, same thing, I keep the defrosters going on high. By the time it clears up, I'm getting out for a coffee, snow gets back in the truck, starts over. I do have a deflector on the plow, but some still blows over.


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## LapeerLandscape (Dec 29, 2012)

rich414 said:


> Agreed on the cowling packing with snow, stops the fresh air and fresh air is DRY recycles air is WET. i am plowing a 4 mile subdv road, so whats your suggestion to keeping the snow out of the cowling area? when the snow is not packing up there is NO moisture issue.


Plow slower so the snow rolls off the plow and not over the top. I know it seems to take forever but really what takes longer is trying to clear the moisture.


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## Mark Oomkes (Dec 10, 2000)

In all the equipment I've plowed in, I've always had to keep a window open in order to keep the windows defogged...whether it has AC or not. Everything can be dry inside, but it will fog up unless I have a window cracked. Not always the case in trucks.


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## MIDTOWNPC (Feb 17, 2007)

I use Rain ex anti fog and wipe down the windows whenever the machines get a break and a wash down. Keeps the sidewalk tractors from fogging up and the operators get in and out of those a lot more then anything else. It’s a small bottle that looks like lighter fluid


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## leigh (Jan 2, 2009)

I've got a 2004.5 and what you describe has never happened with my truck. I'm stumped ! I'll sleep on it. Hate these obscure issues, they'll drive you mad!


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## Mebes (Feb 7, 2004)

In my experience humidity in larger cab trucks is always harder to deal with compared to standard cabs so the best option in my experience is to keep that cowling clear.

Ice build up in my case (Ford) usually comes from snow melting off the windshield then re-freezing below the wiper area mucking up the intake.

Depending on conditions the best way i have found to deal with this is to keep the windshield as cold as possible by stuffing rags up on the dash to block vents setting the heat to max and blowing it on the floor so the snow never melts on the windshield in the first place.

If you can cool down the glass quickly enough or start with cold glass and keep it that way and keep moving so it stays cold the snow that hits the windshield simply blows off in the wind as you go down the road.

Problem with this is if your cab gets to hot and/or you stop for too long the heat from your cab starts to warm the glass then the party is over.


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## leigh (Jan 2, 2009)

Have you tried driving naked? Its an option with these extreme issues.


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## 1olddogtwo (Aug 6, 2007)

I can't plow with the window up.

It's always open unless heavy wind.


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## tpendagast (Oct 27, 2012)

rich414 said:


> Guys, in a 2004 duramaz 4x where is the fresh air intake for the cab located? i want to block this off to see if this stops the moisture issue. When the snow builds up on the windshield, under the wipers the moisture increases in the cab to the point there is water on the inside of the cab. I remove the snow buildup, tried driving with the windows cracked, the A/C will not work in cold weather, tried recirc air, not fresh, looked on GMpartsonline to try and figure this out and there parts diagrams are poor at best, but no real details. any suggestions are appreciated!! happy new years!!


Not gm, but I had that on an f350 and it ended up being the deal for the windshield that was leaking 
Would actually drip from the top like there was a roof leak there was so much moisture


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## Mark Oomkes (Dec 10, 2000)

1olddogtwo said:


> I can't plow with the window up.
> 
> It's always open unless heavy wind.


Nothing better than getting hit in the face with slush because the window is open...


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## tpendagast (Oct 27, 2012)

rich414 said:


> Agreed on the cowling packing with snow, stops the fresh air and fresh air is DRY recycles air is WET. i am plowing a 4 mile subdv road, so whats your suggestion to keeping the snow out of the cowling area? when the snow is not packing up there is NO moisture issue.


Maybe get a metal snow FOIL instead of the rubber flap 
The snow foil helps curl the snow and shoot it over drifts like a snow blower if you get going fast enough


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## SilverPine (Dec 7, 2018)

1olddogtwo said:


> I can't plow with the window up.
> 
> It's always open unless heavy wind.


Theres people that plow with the window up? Scary.


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## Mr.Markus (Jan 7, 2010)

Mark Oomkes said:


> Nothing better than getting hit in the face with slush because the window is open...


It's so refreshing and wakes you up for more fun in snow, I mean who here dislikes plowing snow for a living...!?
It never just hits me in the face by the way, it's like a sunami that covers my whole left side and lap...


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## EWSplow (Dec 4, 2012)

Mr.Markus said:


> It's so refreshing and wakes you up for more fun in snow, I mean who here dislikes plowing snow for a living...!?
> It never just hits me in the face by the way, it's like a sunami that covers my whole left side and lap...


By spring, my left shoulder muscles are like a rubber band. My massage therapist spends hours working on that. She said its from the open window Unfortunately, she's a professional and...


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## Randall Ave (Oct 29, 2014)

EWSplow said:


> By spring, my left shoulder muscles are like a rubber band. My massage therapist spends hours working on that. She said its from the open window Unfortunately, she's a professional and...


Shure she is.


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## zlssefi (Dec 29, 2011)

Check your cab vents behind the rear seat if its a crew cab. sometimes the rubber flaps dry out and fall off leaving a nice open hole for water to get in.


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## SilverPine (Dec 7, 2018)

zlssefi said:


> Check your cab vents behind the rear seat if its a crew cab. sometimes the rubber flaps dry out and fall off leaving a nice open hole for water to get in.


And mice.


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## leolkfrm (Mar 11, 2010)

have you tried keeping the fan higher and temp down to keep air moving?


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## iceyman (Mar 1, 2007)

leigh said:


> Have you tried driving naked? Its an option with these extreme issues.


Like 5 years ago we had a blizzard with like 5* temps and im driving in shorts and a tshirt with ac on here and there.. my monkeys wanted to kill me when they got back in the truck


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## Philbilly2 (Aug 25, 2007)

1olddogtwo said:


> I can't plow with the window up.
> 
> It's always open unless heavy wind.


How many times have you smashed your forehead off the window on a windy night that you have to have it closed?  :laugh:

I thought I lost my front teeth one night when I had it half way up and tried to back up right along the side of a dumpster enclosure.


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