Heater control questions ???? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**landarts** · 01-11-2010, 04:48 PM

I have a 72 1/2ton that I rebuilt the ac/heater control it had broken levers. I also replaced the heater core that was bad. I made sure all the vacuum tubes were hooked up and greased the cables. It blows really hot which is a good thing, when I position the levers in certain positions it activates the the fresh air door on the passenger side. It seems to only blow out of the bottom and defrost vent and very little comes out of the center or side dash vents. What position are the levers supposed to be in to activate the dash center and side vents. Or is something possible screwed up inside of the heater not allowing the proper door to deflect to those outlets????

**clay68c10** · 01-12-2010, 01:35 AM

There's a flapper box for the dash vents, the flap does get sloppy in them and then you get low or no flow. I don't have a pic, but it's the part of the ductwork below/behind the left side of the glovebox.

**clay68c10** · 01-12-2010, 01:39 AM

Here's some pics

http://67-72chevytrucks.com/vboard/s...highlight=flap

**landarts** · 01-12-2010, 10:54 AM

Hey thanks for the suggestions....I will pull it apart and see if that flap is working or broken, thanks again Jim

01-11-2010, 04:48 PM	#1
landarts landarts Join Date: May 2005 Location: Star, Idaho Posts: 1,417	Heater control questions ???? I have a 72 1/2ton that I rebuilt the ac/heater control it had broken levers. I also replaced the heater core that was bad. I made sure all the vacuum tubes were hooked up and greased the cables. It blows really hot which is a good thing, when I position the levers in certain positions it activates the the fresh air door on the passenger side. It seems to only blow out of the bottom and defrost vent and very little comes out of the center or side dash vents. What position are the levers supposed to be in to activate the dash center and side vents. Or is something possible screwed up inside of the heater not allowing the proper door to deflect to those outlets????

01-12-2010, 01:35 AM	#2
clay68c10 Senior Member Join Date: Aug 2004 Location: Centennial, CO Posts: 2,990	Re: Heater control questions ???? There's a flapper box for the dash vents, the flap does get sloppy in them and then you get low or no flow. I don't have a pic, but it's the part of the ductwork below/behind the left side of the glovebox. __________________ 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 Last edited by clay68c10; 01-12-2010 at 01:36 AM. Reason: typo

01-12-2010, 01:39 AM	#3
clay68c10 Senior Member Join Date: Aug 2004 Location: Centennial, CO Posts: 2,990	Re: Heater control questions ???? Here's some pics http://67-72chevytrucks.com/vboard/s...highlight=flap __________________ 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

01-12-2010, 10:54 AM	#4
landarts landarts Join Date: May 2005 Location: Star, Idaho Posts: 1,417	Re: Heater control questions ???? Hey thanks for the suggestions....I will pull it apart and see if that flap is working or broken, thanks again Jim



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