Defrost/defog not defogging (1 Viewer)

[93yotasr5]

So I've searched, and all I can find are things related to the heater core.

Here's the issue. On days like today where it is rainy or when the windshield fogs up the defrost vents will not clear the windshield. It actually makes it worse, and In some instances i have even seen some steam coming out of the vents. I do not get a sweet smell, or any smell resembling coolant. There is actually no smell when it steams leading me to believe it is not the heater core. What are some things I should check?

Thanks

 

[ppc]

In those conditions the AC needs to be running

 

[Kernal]

In addition to above if you have water leaking inside the vehicle (windshield ever replaced?) the increased humidity (in the cabin) could cause fogging of the windows. Carpet wet in the footwells?

 

[93yotasr5]

I've never had to run the ac to defogging the Windows before.

I have had the windshield replaced a couple times since I've owned it. Sometimes the passenger carpet is a little damp.

 

[Cruzerman]

I always use the AC when defogging. With no AC, my defogger does very little. With AC, works like a champ.

 

[slow95z]

I've never had to run the ac to defogging the Windows before.

I have had the windshield replaced a couple times since I've owned it. Sometimes the passenger carpet is a little damp.

it comes on when you put it in defrost automatically

 

[bmwjnky]

Maybe the drains for the AC evaporator are clogged and when you run the heater it heats the water in that has pooled up making it worse. Just a guess.

On a somewhat related note does anyone have a fix for the rear defogger? Mine only has about 3 or 4 lines that do anything.

 

[93yotasr5]

it comes on when you put it in defrost automatically

Almost certain that didn't start until 95. I know for a fact my ac does not come on with the defrost button.

 

[IanB]

Almost certain that didn't start until 95. I know for a fact my ac does not come on with the defrost button.

On my '91 and my '93 HDJ81's, the defrost button does also light the AC button on the HVAC controls. The AC removes moisture from the air, helping de-fog the windows, it's not used for cooling in this instance.

 

[93yotasr5]

Very weird. Mine doesn't and had never come on with the defrost.

 

[IanB]

Very weird. Mine doesn't and had never come on with the defrost.

I should clarify, ONLY with full defrost, not the defrost/footwell setting.

 

[Squash]

Make sure you select out side air and not the cabin recirc.

 

[93yotasr5]

Make sure you select out side air and not the cabin recirc.

for sure!

@Kernal made a suggestion to check my windshield near the dash area. I did and I believe that is my culprit. It seems that there is some water coming from the bottom of the windshield. There is currently a crack in the windshield so I will need it replaced anyways. When i have it replaced Ill makde sure it gets sealed correctly.

Thanks for the help everyone.

 

[LS1FJ40]

I think you have multiple problems. As was mentioned above you need to have the AC on and outside air coming in. The AC dries the air, pulling the moisture out. When the AC went out on my 92 I didn't think it was a big deal, just rolled the windows down. Until winter came. It was nearly impossible to see at times. I ended up having to run a cigarette lighter fan and would wipe the windshield with a towel. It sucked. Repaired my AC last fall and this past winter I had no problems.

 

[93yotasr5]

just came out to my truck this am and found a nice pool of coolant on the passenger side floor mat. I guess this has been my issue all along.:/ now comes the hard part of finding a new one. I am going to unhook the hose that goes to the core and just plug it until I can find a replacement.