Heater Defrost Issue

[Justin Fleming]

Ok K5 Gurus, the issue that I have is that the driver side defrost has great volume of flow, the passengers is only about 1/3 the flow and the window is always iced up. How can I even out the flow or just improve the flow on the passengers side.....

 

[Stomis]

Thats odd considering the heater box is located under the passenger side.

Not really much can be going on. You've either got a broken flap/diverter or something fell down your pass vent. Also could be a damn mouse nest. Easiest place to start would be looking under the dash and seeing if any of the external stuff on the air box appears broken.

 

[72blazerguy]

I would check the venting. The vent tube can come apart.

My 71 blazer had low air output which I attributed to a crappy heating system, but turned out it had leaves and crap around the heater core and the vent system was in shambles. The wet gunk was restricting air flow and air that was getting past was blowing out behind the dash. Cleaned out the leaves, put all the tube back together and it works just fine

From the factory, these systems should work good.

 

[Justin Fleming]

So I pulled the glove box out, remove a cover and I believe this is what is the bend door. that all seemed to be there and the little plastic tang thing was not broken as I have seen in the parts. I pulled the dash pad off and I cant see anything looking from a top. and I can not seem to see where the defrost vents tie into the heater box..... Cant really see much....

where to go from here?

 

[Justin Fleming]

Any other ideas?

 

[Stomis]

Not for certain but having a crap load of pressure out of one vent and not much pressure out of the other could be a flap broken open too far and air just taking the path of least resistance. My point is what seems like it might be ok might be wrong say if the driver side flap is only suppose to be open 1/2 way so theres still pressure into the pass side passage.

 

[Justin Fleming]

Does anyone have some experience with the heater plenum boxes and able to give me some advise where to start and what to be looking for/how to even get to see it.....

 

[Justin Fleming]

anyone?

 

[blazer74]

Flap favors the drivers due to the way it hinges if I recall correctly but I'd guess you have a restriction/ blockage on the pass side.

The flap is on top and pretty much centered on the truck.

I've got a box somewhere I can get a pic but won't be right away.

You can try and fish down from the top but your might have to remove the heater box.

You can see the diaphragm that operates the defrost door above and right of the gas pedal.

 

[Justin Fleming]

bump for additional advise..

 

[Justin Fleming]

bump for additional advise..

 

[82355]

You are just going to have to tear it apart and see what is going on in there.

Martin