Heater blows constantly - The 1947 - Present Chevrolet & GMC Truck Message Board Network

RShaips · 09-27-2008, 04:57 PM

I replaced the switch but it didn't change. The switch works and adjusts the speed of the blower but it runs on low constantly. Any help? Thanks

andresco50 · 09-27-2008, 10:04 PM

My truck dont have an off position, it never turns off, I read that in the Owners manual

6772fan · 09-27-2008, 10:22 PM

I've had a lot of these trucks and everyone of them had a constant low speed fan at all times. I think it's normal.

**78 Big10 454** · 09-28-2008, 12:00 AM

I bought my 78 new in Dec. of 77. The salesman told me that the blower will always be on low. Chevrolet called it "Astro- Ventilation" or some type of nonsense.

stepside454 · 09-28-2008, 03:26 AM

yep, most all GM cars & trucks through the mid 80s did that

RShaips · 09-28-2008, 08:53 AM

Well I guess I will quit messing with it. Even though I would like it to be off! Thanks

74 C-30 · 09-28-2008, 09:33 AM

to shut it off open the hood and unplug the single wire going to the heater box. we do that to our dump truck in corn cutting season incase corn gets down in the core, when you want ti back on for winter just plug it back in

**Captkaos** · 09-28-2008, 12:55 PM

It is a feature. "Flow Through Power Ventilation" All of them do this.

**78 Big10 454** · 09-29-2008, 01:31 AM

Thanks for the correction on the name, Capt. I knew it was something kinda trick sounding.

Duro5341 · 09-29-2008, 12:49 PM

This must have been an option, my 86 K10 custom deluxe has no a/c, manual windows, and locks....and i can turn my heater box, and the blower motor to the OFF position

However my 79 Monte Carlo has no A/C manual locks, and power windows, and the blower motor never turns off

Duro

pilotj · 09-29-2008, 05:34 PM

Don't know if you have a/c or not, But on my '79(has a/c), I lifted the hood and snipped the yellow wire that plugs into the blower motor resistor (bolted down into the top of the ac/heater box). It should have a light blue, dark blue, brown and yellow wire on the plug(yellow being the end single in the plug). I still have low, med and high speed; just dosen't run on low all the time now. Seems like it always blew hot air to me! Don't need that kind of flow through ventilation when skunks stink it up around here!

andresco50 · 09-29-2008, 10:36 PM

I unpluged the blower motor that's all

79gmcsierragrande · 09-30-2008, 11:09 PM

I just put a toggle switch on mine. I didn’t like the fan blowing all the time.

09-27-2008, 04:57 PM	#1
RShaips Senior Member Join Date: Jun 2002 Location: Augusta Missouri Posts: 804	Heater blows constantly I replaced the switch but it didn't change. The switch works and adjusts the speed of the blower but it runs on low constantly. Any help? Thanks

09-27-2008, 10:04 PM	#2
andresco50 Registered User Join Date: Jan 2008 Location: Lakeworth, Fl Posts: 633	Re: Heater blows constantly My truck dont have an off position, it never turns off, I read that in the Owners manual __________________ 2001 silverado 2wd 2003 silverado 4wd 1975 scottsdale c10 (project)

09-27-2008, 10:22 PM	#3
6772fan Active Member Join Date: Jan 2004 Location: East Texas Posts: 380	Re: Heater blows constantly I've had a lot of these trucks and everyone of them had a constant low speed fan at all times. I think it's normal. __________________ Lane 1979 Chevy SWB- (Second owner- Father in Law was first) 1979 Chevy Silverado SWB-Red/Red

09-28-2008, 12:00 AM	#4
78 Big10 454 78 Big10 454 Join Date: Jul 2008 Location: Pismo Beach, CA Posts: 839	Re: Heater blows constantly I bought my 78 new in Dec. of 77. The salesman told me that the blower will always be on low. Chevrolet called it "Astro- Ventilation" or some type of nonsense.

09-28-2008, 03:26 AM	#5
stepside454 Registered User Join Date: Nov 2003 Location: st. louis area Posts: 1,551	Re: Heater blows constantly yep, most all GM cars & trucks through the mid 80s did that __________________ 75 GMC C-15 short/step factory 454, lowered

09-28-2008, 08:53 AM	#6
RShaips Senior Member Join Date: Jun 2002 Location: Augusta Missouri Posts: 804	Re: Heater blows constantly Well I guess I will quit messing with it. Even though I would like it to be off! Thanks

09-28-2008, 09:33 AM	#7
74 C-30 Dually Pride Join Date: Jun 2008 Location: NH Posts: 540	Re: Heater blows constantly to shut it off open the hood and unplug the single wire going to the heater box. we do that to our dump truck in corn cutting season incase corn gets down in the core, when you want ti back on for winter just plug it back in __________________ If I have to explain, you wouldn't understand. '74 Chevy C-30 350/4 speed/dually '94 Ford Ranger Last edited by 74 C-30; 09-28-2008 at 09:34 AM.

09-28-2008, 12:55 PM	#8
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Re: Heater blows constantly It is a feature. "Flow Through Power Ventilation" All of them do this. __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

09-29-2008, 01:31 AM	#9
78 Big10 454 78 Big10 454 Join Date: Jul 2008 Location: Pismo Beach, CA Posts: 839	Re: Heater blows constantly Thanks for the correction on the name, Capt. I knew it was something kinda trick sounding.

09-29-2008, 12:49 PM	#10
Duro5341 Registered User Join Date: Dec 2006 Location: Earth Posts: 239	Re: Heater blows constantly This must have been an option, my 86 K10 custom deluxe has no a/c, manual windows, and locks....and i can turn my heater box, and the blower motor to the OFF position However my 79 Monte Carlo has no A/C manual locks, and power windows, and the blower motor never turns off Duro __________________ -1986 K10 LWB, 350 HD,TH400 3.08, 30 spline 10 bolt, with an Auburn Posi, 31" tires All original, second owner truck -1979 Monte Carlo, 350, 200r4, 3.73 posi -1987 GT T-top Mustang - slow moving project Last edited by Duro5341; 09-29-2008 at 12:50 PM.

09-29-2008, 05:34 PM	#11
pilotj Registered User Join Date: May 2007 Location: Roanoke, VA Posts: 78	Re: Heater blows constantly Don't know if you have a/c or not, But on my '79(has a/c), I lifted the hood and snipped the yellow wire that plugs into the blower motor resistor (bolted down into the top of the ac/heater box). It should have a light blue, dark blue, brown and yellow wire on the plug(yellow being the end single in the plug). I still have low, med and high speed; just dosen't run on low all the time now. Seems like it always blew hot air to me! Don't need that kind of flow through ventilation when skunks stink it up around here! __________________ 1979 Chevy C20 350/TH400 1974 Chevy C30 350/4speed

09-29-2008, 10:36 PM	#12
andresco50 Registered User Join Date: Jan 2008 Location: Lakeworth, Fl Posts: 633	Re: Heater blows constantly I unpluged the blower motor that's all __________________ 2001 silverado 2wd 2003 silverado 4wd 1975 scottsdale c10 (project)

09-30-2008, 11:09 PM	#13
79gmcsierragrande Manual Transmission Club Join Date: May 2008 Location: Grand Junction CO Posts: 292	Re: Heater blows constantly I just put a toggle switch on mine. I didn’t like the fan blowing all the time. __________________ 79 GMC Sierra Grande, SWB, Heavy Half If I wanted easy I would just buy a NEW truck!



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