The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 10-27-2024, 05:20 PM   #1
kna4977
Senior Member
 
Join Date: Jul 2006
Location: Midlothian TX
Posts: 448
Air from dash outlets only

Have cool air and hot air, but regardless if I put it on heater or defroster the air always comes out the dash vents. The top lever that says inside outside defroster de-ice is very difficult to move but it does turn the door I can see under the dash. The middle one turns off and on the a/c compressor is easy to move but never directs air through anything but the dash vents. The fan and cold hot work as they should.
kna4977 is offline   Reply With Quote
Old 10-27-2024, 05:48 PM   #2
dmjlambert
Senior Member
 
dmjlambert's Avatar
 
Join Date: Apr 2016
Location: Cypress, TX
Posts: 3,803
Re: Air from dash outlets only

It's time to take apart the duct system and see what you have going on in there. Start with the metal box above the transmission hump, remove it. Work your way toward the passenger side, remove the S-duct. Remove the dash/floor selector box. Examine the function of the flapper in there. Mine was bad. That selector box is reproduced, and you may also be able to find a used good one in the parts section. That's what I did.
dmjlambert is offline   Reply With Quote
Old 10-29-2024, 10:38 PM   #3
PanhandleShantyman
Junior Member
 
PanhandleShantyman's Avatar
 
Join Date: Dec 2023
Location: Pensacola, FL
Posts: 35
Re: Air from dash outlets only

I don't know about the AC/heater systems, mine just has heater, but it seems like in general the most common problems with air flow direction come from rusted/seized control cables, and/or busted pot metal control arms attached to them at the control panel. Bad flappers are probably less common but that stuff can wear out too... On my old truck, which seems to have all the most common problems, it was all issues with seized and busted cables and control arms. And all of that had led to structural issues with the heater control panel itself falling apart in the back and needed reinforcement at the sprung rivets, so all the necessary leverage was available. As the experienced Mr. DMJLambert says above, there's no substitute for pulling all that stuff out and seeing how it looks.
PanhandleShantyman is offline   Reply With Quote
Old 10-30-2024, 08:15 AM   #4
clay68c10
Senior Member
 
clay68c10's Avatar
 
Join Date: Aug 2004
Location: Centennial, CO
Posts: 2,979
Re: Air from dash outlets only

Your diverter flap is broken. It's plastic and a common breakage item. The arm attached to it has the piece that actuates the compressor switch, so your controls and cable are ok.
Replace the diverter box and lube up the cables and control head while you have it apart.
__________________
ClusterTruck: 68 C10 Bought in 89, wrecked in 03. Slow low $ rebuild started '17. 6.0 & TKO
http://67-72chevytrucks.com/vboard/s...d.php?t=788602
93 K1500 Short Step, 350, NV4500, EBL flash ECU. Vortec heads & roller cam someday...
05 Jeep Wrangler Unlimited. 3” lift & 6-speed
02 E320 the insurance total “free car”
13 Tahoe LTZ
clay68c10 is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 04:28 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com