Need help - heater seems to be stuck on - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Mountain Man · 06-26-2002, 09:31 PM

O.K., so my truck is getting very hot in the cab. I discovered that heat is blasting out of the center floor duct, even though my heat control is all the way off. Is it possible that it is stuck open, or my dash control is binding some where.

Before I go crazy and start ripping and tearing, is there a way to close a flap or something inside that center heat duct.

The truck is only a fair weather summer driver, not driven in winter so I don't even need the cab heat.

What is the quickest way to block the heat from blowing out my center floor duct???

WORNBRAKES · 06-26-2002, 10:21 PM

If I'm not mistaken there is one wire that runs into the front of your fuse block with a terminal end. Blue I think. If you pull that wire your heat should not work at all. Hope this helps.
Mario
P.S. If that dont work maby try some duct tape. lol

Sierra · 06-26-2002, 10:21 PM

Sounds as if the heater control valve may have failed open. If you lose vacuum to the valve, which is supplied by a small rubber hose, it will open and allow hot coolant through the heater core. The valve is mounted on passenger-side inner fender on my truck. Hope this helps.
Tim

too many · 06-27-2002, 12:39 AM

If you never need heat,
Just unhook the heater hoses under the hood from the heater core, and "loop" them together.

hwedding56 · 06-27-2002, 09:37 AM

STOP!! Don't start pulling and plugging. Go to the parts store and ask for a heater control valve. They make a manuel shut off for about 4 bucks. Mine went bad with the vacume control valve. It is nothing but a valve that you just open in the winter and close in the summer takes about 2 minutes. Just cut hose install and close. Hope this helps.
Herbie
PS. Get two hose clamps also. LOL

Blue68 · 06-27-2002, 11:29 AM

I'm with the last two guys. For a quick fix, just loop the hose from the pump to the intake. I'm doing this for now because my header and a/c units are sitting on a shelf so I can drive it. If you do us the system in the winter ( or in Canada anytime but the summer, note I'm from Texas) and you want heat, get a shutoff valve. This is actually the way the Vintage Air system works, there is a manual valve that is controlled by the hot cold lever.

**Downtown** · 06-27-2002, 07:12 PM

You didn't say if your truck had factory a/c or not. If it has a/c then what is said about the vacuum to open and close the valve is correct. If it doesn't have a/c, then it should have two temperatures. Hot and really hot. Buy the manual shut off valve to keep hot water out of the heater coil.

Mountain Man · 06-27-2002, 09:36 PM

hwedding56 - Thanks for the idea. I think that the shut off valve is the best way to go. Which hose do I put the valve on to.

If you are looking at the heater core box from the front, is it the upper line or the lower line that I would put the shut off valve into the line.

I do not have a/c.

Thanks in advance.

06-26-2002, 09:31 PM	#1
Mountain Man Registered User Join Date: Jan 2002 Location: Calgary, Alberta, Canada Posts: 451	Need help - heater seems to be stuck on O.K., so my truck is getting very hot in the cab. I discovered that heat is blasting out of the center floor duct, even though my heat control is all the way off. Is it possible that it is stuck open, or my dash control is binding some where. Before I go crazy and start ripping and tearing, is there a way to close a flap or something inside that center heat duct. The truck is only a fair weather summer driver, not driven in winter so I don't even need the cab heat. What is the quickest way to block the heat from blowing out my center floor duct??? __________________ 72 C10 Cheyenne Super Full trim Factory tach dash A/C dash Factory tilt 350 / 350 power train - with Edelbrock components.

06-26-2002, 10:21 PM	#2
WORNBRAKES Senior Member Join Date: Jul 2001 Location: Hughesville, MD Posts: 1,350	If I'm not mistaken there is one wire that runs into the front of your fuse block with a terminal end. Blue I think. If you pull that wire your heat should not work at all. Hope this helps. Mario P.S. If that dont work maby try some duct tape. lol __________________ Mario and Mandy Hughesville, MD 20637 69 C10 305/350 71 K5 Basket case 75 K10 Rescue Parting out 77 MG Midget Parting out 15 6.7L Cummins

06-27-2002, 09:37 AM	#5
hwedding56 Registered User Join Date: Oct 2001 Location: Ky Posts: 255	STOP!! Don't start pulling and plugging. Go to the parts store and ask for a heater control valve. They make a manuel shut off for about 4 bucks. Mine went bad with the vacume control valve. It is nothing but a valve that you just open in the winter and close in the summer takes about 2 minutes. Just cut hose install and close. Hope this helps. Herbie PS. Get two hose clamps also. LOL __________________ 67-CST Factory PS PB AIR Buckets SWB FLEET 350-700r4 67-SWB Step Plain Jane 350-3 on the tree 68 1-1/2 ton Dump 12' rock Bed soon to have fast68's 292 installed 72 GMC 3/4 ton Crew Cab 402 BBL 400 tranny ( ok I bought it from Crews) Its one ugly long WB long bed 4 door truck!!!!!!!!!

06-27-2002, 11:29 AM	#6
Blue68 Registered User Join Date: Apr 2000 Location: Frisco, Tx, USA Posts: 606	I'm with the last two guys. For a quick fix, just loop the hose from the pump to the intake. I'm doing this for now because my header and a/c units are sitting on a shelf so I can drive it. If you do us the system in the winter ( or in Canada anytime but the summer, note I'm from Texas) and you want heat, get a shutoff valve. This is actually the way the Vintage Air system works, there is a manual valve that is controlled by the hot cold lever. __________________ http://home.comcast.net/~r.landrum/w...tos.html-.html '68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades.

06-27-2002, 07:12 PM	#7
Downtown Senior Member Join Date: Dec 1999 Location: New Palestine, IN Posts: 471	You didn't say if your truck had factory a/c or not. If it has a/c then what is said about the vacuum to open and close the valve is correct. If it doesn't have a/c, then it should have two temperatures. Hot and really hot. Buy the manual shut off valve to keep hot water out of the heater coil. __________________ 72 Super Cheyenne Longbed 350 49,000 original miles and My dad ordered it new 66 Chevy Caprice 2 dr 77 Caprice Estate Wagon New Palestine, IN

06-26-2002, 10:21 PM	#3
Sierra Registered User Join Date: Nov 2000 Location: Victoria, Texas Posts: 71	Sounds as if the heater control valve may have failed open. If you lose vacuum to the valve, which is supplied by a small rubber hose, it will open and allow hot coolant through the heater core. The valve is mounted on passenger-side inner fender on my truck. Hope this helps. Tim

06-27-2002, 12:39 AM	#4
too many Registered User Join Date: Jul 2001 Location: nw IL Posts: 211	If you never need heat, Just unhook the heater hoses under the hood from the heater core, and "loop" them together.

06-27-2002, 09:36 PM	#8
Mountain Man Registered User Join Date: Jan 2002 Location: Calgary, Alberta, Canada Posts: 451	hwedding56 - Thanks for the idea. I think that the shut off valve is the best way to go. Which hose do I put the valve on to. If you are looking at the heater core box from the front, is it the upper line or the lower line that I would put the shut off valve into the line. I do not have a/c. Thanks in advance. __________________ 72 C10 Cheyenne Super Full trim Factory tach dash A/C dash Factory tilt 350 / 350 power train - with Edelbrock components.

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