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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: Chisholmcody on September 26, 2014, 10:54:46 pm

Title: Blower motor
Post by: Chisholmcody on September 26, 2014, 10:54:46 pm
Today I was thinking...... Is there any way to turn the blower motor off all the way so it doesn't blow in hot summer air? Or is there any way to bypass it so it's not on unless I want it on?

Thanks in advance,


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Title: Re: Blower motor
Post by: bake74 on September 27, 2014, 09:27:08 am
     I assume you have an earlier truck like my 74 where it blows all the time.  You can unplug the wire from the motor or install a switch to kill it by installing it inline withe the power wire.
Title: Re: Blower motor
Post by: Chisholmcody on September 27, 2014, 11:50:03 am
Will this hurt anything in the truck or will it be fine?
Title: Re: Blower motor
Post by: FlatBlack77 on September 27, 2014, 03:32:44 pm
just unplug it. it will be fine.

my 77 and 79 both have the motors running all the time so maybe its all years?

both of them are A/C trucks but my dads old 78 non A/C truck did the same
Title: Re: Blower motor
Post by: VileZambonie on September 27, 2014, 06:49:43 pm
It was designed that way to prevent stagnant air and mold
Title: Re: Blower motor
Post by: FlatBlack77 on September 27, 2014, 10:10:14 pm
thats what i have read but Bake said about older trucks so i figured there was some kinda cutoff year where it they stopped making them like that.
Title: Re: Blower motor
Post by: Chisholmcody on September 27, 2014, 11:59:50 pm
Ok good to know I might just wire up a toggle switch under the dash


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Title: Re: Blower motor
Post by: FlatBlack77 on September 28, 2014, 12:38:23 pm
im considering doing the same thing. on humid mornings as soon as i turn the ignition on, the blower comes on and just that little bit of airflow fogs the windshield all up and it doesnt go away till the truck gets warm enough to blow some heat >:(
Title: Re: Blower motor
Post by: bd on September 28, 2014, 04:37:30 pm
Although I don't advocate defeating the "low speed fan always running" for the very reason Vile made clear, if you really have a problem with the feature, and don't mind eliminating low speed entirely, you can simply remove the brown wire from the resistor and tape it up (this allows you to reinstall it if you decide you don't like the way it works).  In doing so, Low speed will become OFF.  You will still have Medium and High fan speeds.
Title: Re: Blower motor
Post by: FlatBlack77 on September 28, 2014, 04:46:46 pm
I like that idea I might try that
Title: Re: Blower motor
Post by: Chisholmcody on September 29, 2014, 02:11:33 pm
Yeah I might go the brown wire route thanks for the tip bd!
Title: Re: Blower motor
Post by: rich weyand on October 01, 2014, 01:02:08 pm
Friend of mine was a GM mechanic back in the day.  He said that after working on the heater/AC, they were required by law to test the system to make sure the blower motor ran in Low all the time, and that it maintained a certain cabin air pressure with all the windows and vents closed.  They had a pressure gauge they put in top of the window to test it.  It had to do with preventing exhaust infiltration.
Title: Re: Blower motor
Post by: FlatBlack77 on October 01, 2014, 10:34:25 pm
fancy

i love hearing about stuff like that
Title: Re: Blower motor
Post by: LTZ C20 on October 02, 2014, 12:53:15 am
I agree. That's pretty cool.
Title: Re: Blower motor
Post by: rich weyand on October 02, 2014, 09:27:21 am
Yeah, he said that the requirement applied to trucks because they were considered by regulators to be fundamentally different than cars, because: they might be left to idle on the job site for long periods; they were less well sealed in the first place; someone might spend their whole working day every day in the cab; and because they were more likely to be modified, with toppers, campers, winches, plows, work lights, mirrors and other things that might include penetration of the firewall and cab body with electrical harnesses and mechanical additions.

Dunno.  That's what he said, and it makes some sense to me.  Of course the mold and mud explanation makes some sense to me too.
Title: Re: Blower motor
Post by: LTZ C20 on October 02, 2014, 09:46:39 am
It seems that both reasons serve a valid purpose. I like to hear little random tid bits like that.
Title: Re: Blower motor
Post by: Chisholmcody on October 02, 2014, 01:24:42 pm
Yeah does make a lot of since on why they had it on low all of the time