Defrost ducts questions

[Kamikaze12volts]

Does the M715 supposed to have air ducts between the cowl dash and the winsdshield frame ?? I remember that i have two big acces in my weatherstip but i can't remember if i have something on the frame itself or in the cowl dash.

Because right now i have a lot of heat in my truck ... but the windshield still freezing because no hot air comming from the dash ... i think mine is completly sealed or those vents are not opened ...

If someone can post some good pictures of the cowl dash without frame and the base of the frame itself. Rignt now in canada i'm receiving some freezing rain and got about 1" thick of ice on the truck ... so a defrost could be very handy by those days.

Thanks a lot !!!

[randyscycle]

There should be two slots in the cowl on the body, then two slots in the weather strip, then two slots in the windshield frame that allows the air to flow out of the two vents to the glass. When the shield is up, then the air should be able to flow through all the layers to the glass.

There are two defroster plenums that mount under the dash to two small studs that are welded to the bottom of the cowl.

[airborne]

Check to see if the 'floor/defroster' lever is moving, kinda sounds like it's not.

[randyscycle]

Didn't think about that.....

I also have found the floor/defrost door can come loose from the shaft and stay stuck in one position in some heater systems.

[brute4c]

The defrost, when hooked up and working good, isnt the most effective in temps below 0...by -20 you have to keep a scraper in the cab for the inside of the windshield...

[Tomahawk715]

Perhaps adding a booster fan would help? They make them for VW beetles-mount under the rear seat in the supply line--Bugs were notorious for no air to windshield. Mounted right out of the air box it should really provide some air.

[Kamikaze12volts]

Thanks but i'm not gaving a fsj heater , mine is a bus unit with 2 speed fan on it ... and i add a recirculation fan under the dash ... even in -20 running under 30mph a can heat the entire cab and melt every ici on the floor ... but the windshild icing inside. I have with a flashlight to look at those opening but nothing seems to be opened . Will give another try this afternoon since your all confirm those openings.

And also for those underdash plenums ... can it still be possible to find somes ?? With an 8" fan directly on those plenums ... should be having enough flow !!

[5quarter]

i installed a surplus 12/24v nos heater unit, without the defrost ducts and after a few licks with my squeegy it will keep up with the moisture just fine

[503m715]

Vintage Power Wagons still may have some of the defroster ducts. They put them up for sale on Ebay once and a while.

[Jester]

Vintage Power Wagons still may have some of the defroster ducts. They put them up for sale on Ebay once and a while.

Holy Smokes!!!! They have them listed in the little flyer I have. $40.00/EA