A/C fan motor problems.... Need help! 1977 Blazer - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**oldrustytrucks** · 09-06-2013, 01:43 AM

A/C fan motor problems.... Need help! I'm working on my 77 Blazer. With all A/C and heat levers in the off position my blower motor still runs on a very low speed. I have a couple ideas but I'm hoping someone knows the answer before I start throwing money at switches and relays! Thanks in advance.
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**78 Big10 454** · 09-06-2013, 02:57 AM

My 78 C-10 was equipped with "Astro Ventilation". Don't know if it was standard in 1977. My blower always ran on low speed when the ignition was hot.

**oldrustytrucks** · 09-07-2013, 03:16 AM

Quote:

Originally Posted by 78 Big10 454

My 78 C-10 was equipped with "Astro Ventilation". Don't know if it was standard in 1977. My blower always ran on low speed when the ignition was hot.

Very interesting... I don't care for it. I wonder why gm did this.
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donut · 09-07-2013, 08:55 AM

My '73 did this also. thought I read it was for fresh air circulation. I know recently there was another thread on this. This was on AC and non AC. IIRC someone did use a 4 position switch off a later model truck that would shut it off. Personally, I just live with it, or unplug the blower. (won't blow if there's no power.

)

**oldrustytrucks** · 09-14-2013, 11:30 PM

Thanks to all for the help. I still think having the fan motor running all the time is silly!

motornut · 09-15-2013, 09:40 AM

in a brochure it's called power venting or something close
keeps the fumes out,fresh air in
very annoying i find
i just cut the brown low speed wire on both the non-ACs 78/79s
78 3 speed/79 4 speed

09-06-2013, 01:43 AM	#1
oldrustytrucks Senior Member Join Date: Feb 2012 Location: Tucson, Az. Posts: 395	A/C fan motor problems.... Need help! 1977 Blazer A/C fan motor problems.... Need help! I'm working on my 77 Blazer. With all A/C and heat levers in the off position my blower motor still runs on a very low speed. I have a couple ideas but I'm hoping someone knows the answer before I start throwing money at switches and relays! Thanks in advance. Posted via Mobile Device Posted via Mobile Device

09-06-2013, 02:57 AM	#2
78 Big10 454 78 Big10 454 Join Date: Jul 2008 Location: Pismo Beach, CA Posts: 838	Re: A/C fan motor problems.... Need help! 1977 Blazer My 78 C-10 was equipped with "Astro Ventilation". Don't know if it was standard in 1977. My blower always ran on low speed when the ignition was hot. __________________ 1978 Chevy SWB C-10 2WD 454/400

09-07-2013, 08:55 AM	#4
donut Registered User Join Date: Aug 2009 Location: S.C. Posts: 1,593	Re: A/C fan motor problems.... Need help! 1977 Blazer My '73 did this also. thought I read it was for fresh air circulation. I know recently there was another thread on this. This was on AC and non AC. IIRC someone did use a 4 position switch off a later model truck that would shut it off. Personally, I just live with it, or unplug the blower. (won't blow if there's no power. ) __________________ '86 C-30 dually, 454/tbh400 '73 K-20 350/350/205 (sold ) I'm kinda like duct tape- no real purpose, but handy to have around.

09-14-2013, 11:30 PM	#5
oldrustytrucks Senior Member Join Date: Feb 2012 Location: Tucson, Az. Posts: 395	Re: A/C fan motor problems.... Need help! 1977 Blazer Thanks to all for the help. I still think having the fan motor running all the time is silly!

09-15-2013, 09:40 AM	#6
motornut 78K & 79C Jimmys Join Date: Nov 2009 Location: Ottawa Ont CANADA Posts: 7,901	Re: A/C fan motor problems.... Need help! 1977 Blazer in a brochure it's called power venting or something close keeps the fumes out,fresh air in very annoying i find i just cut the brown low speed wire on both the non-ACs 78/79s 78 3 speed/79 4 speed Attached Images __________________ John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350



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