HVAC issues

[ak diesel driver]

So a few weeks ago I fished these rubbery strips out of the bottom heat duct, everything seemed to still be working normally. This morning it was -3f and I could tell the heater was not putting out it's normal amount of heat for these temps. I can only assume the gasket is from the heat blend door and it's letting in to much fresh air. I called the dealer and they said item is discontinued and no dealers anywhwere have it in stock. I checked LMC and the only thing I could find is item #16. Is this the right part? Also do I have to remove the entire HVAC box to replace? Any other sources for parts?

 

[ak diesel driver]

So I got out my FSM and looked at it but it only showed the exterior view of the box so I called the dealer back and got this internal view of it.I think the temp door is #32? Does it have a gasket?

 

[3500GMC]

I've never been into the HVAC on these yet. Could the defrost vents have ingested a foreign object or something? Maybe you keep junk off the dash though....

Wonder if the t-stat(s) are ok?

 

[WarWagon]

Cycle the doors and see if a actuator is binding. A gasket isn't going to make a big difference in output. Whistle maybe. May have another gasket part binding you up. You don't want to know how to get there... Yes, lots of stuff comes out...

 

[bison]

Les,i would have a looky see if the AC core has been leaking a wee bit,that oily stuff and dust will plug it up. AFAIK All air for the heater comes trough the AC core first.

I had that on my 98,i poked a hole trough the AC core to get the heat going again(AC wasn't working anyway)
Yeah i know,extreme measures are not for everybody

 

[ak diesel driver]

Cycle the doors and see if a actuator is binding. A gasket isn't going to make a big difference in output. Whistle maybe. May have another gasket part binding you up. You don't want to know how to get there... Yes, lots of stuff comes out...

I've been leaning towards the actuators after some internet surfing. Yes your right lot's of stuff has to come out.

 

[ak diesel driver]

Les,i would have a looky see if the AC core has been leaking a wee bit,that oily stuff and dust will plug it up. AFAIK All air for the heater comes trough the AC core first.

I had that on my 98,i poked a hole trough the AC core to get the heat going again(AC wasn't working anyway)
Yeah i know,extreme measures are not for everybody

LOL maybe on my plow truck AC is already disconnected. But I have hopes for reviving my AC