Lost my Blower motor speeds - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chrismoore701 · 09-14-2023, 07:32 AM

I lost the first two (2) speeds on the blower motor on my 79. Stock setup. Where do I look?

Thanks
Chris

kglowacky · 09-14-2023, 08:44 AM

on the engine side of the firewall between the dryer and the firewall there is a electric plug that has 4 or 5 wires on it, this is how the power gets to your fan motor. It is some sort of resistor as I remember. The yellow wire is the lowest motor speed . Check power to each of these. You should get power to one of these at every speed on your switch. if you don't then switch may be bad if you do then resistor is bad. Doing this from total memory as I am not home to confirm. this info based on my 78 with air. Someone jump in if my info is not correct.

Bandit130 · 09-14-2023, 10:17 AM

Quote:

Originally Posted by kglowacky

on the engine side of the firewall between the dryer and the firewall there is a electric plug that has 4 or 5 wires on it, this is how the power gets to your fan motor. It is some sort of resistor as I remember. The yellow wire is the lowest motor speed . Check power to each of these. You should get power to one of these at every speed on your switch. if you don't then switch may be bad if you do then resistor is bad. Doing this from total memory as I am not home to confirm. this info based on my 78 with air. Someone jump in if my info is not correct.

That is correct. It is the resistor and yes the yellow wire is low speed. If you have a 4 speed fan, you can remove the yellow wire from the connector and have a OFF and 3 speeds. This is what I did cause on mine the low speed always blows when key is on. It was really irritating in winter when first start in the morning air blew from vents before truck warms up.

I believe you can still buy a resistor if you need one.

v30crewcab · 09-14-2023, 08:43 PM

I would check the resistor first, as its easy to get to. you can back probe the plug and see if power is getting thru. the fan switch does go bad sometimes as well but its alot more work to get to.

kglowacky · 09-14-2023, 09:38 PM

agree check resistor 1st

Pontiac1976 · 09-15-2023, 03:25 AM

The resistor 1st (burned) out or plug dirty corroded connectors need cleaning. And you may want to check the Gound clean protect. make sure it got 100% good ground.

chrismoore701 · 09-15-2023, 07:28 AM

I think I have two (2) plugs on my AC box, but do not see a resistor. Ill look tonight, any pics of where this would be?

kglowacky · 09-15-2023, 08:25 AM

you cant see the resistor only the plug without removal. 2 Screws after you unplug it. Looks like a toaster element once you get it out,

**Getter-Done** · 09-15-2023, 08:46 AM

Here's a video for location purposes.

Fixing heater blower motor problem on 1987 square...

chrismoore701 · 09-18-2023, 07:18 AM

thanks, will look into that

09-14-2023, 07:32 AM	#1
chrismoore701 Registered User Join Date: Dec 2004 Location: Highland, IN Posts: 2,318	Lost my Blower motor speeds I lost the first two (2) speeds on the blower motor on my 79. Stock setup. Where do I look? Thanks Chris __________________ Chris _______________________________ 1979 Chevy Stepside SPORT 2018 Chevy Silverado, 39 years apart My build 2008-2016. http://m.imgur.com/a/bURrE

09-14-2023, 08:44 AM	#2
kglowacky Registered User Join Date: Mar 2020 Location: The Woodlands,Tx Posts: 559	Re: Lost my Blower motor speeds on the engine side of the firewall between the dryer and the firewall there is a electric plug that has 4 or 5 wires on it, this is how the power gets to your fan motor. It is some sort of resistor as I remember. The yellow wire is the lowest motor speed . Check power to each of these. You should get power to one of these at every speed on your switch. if you don't then switch may be bad if you do then resistor is bad. Doing this from total memory as I am not home to confirm. this info based on my 78 with air. Someone jump in if my info is not correct.

09-14-2023, 08:43 PM	#4
v30crewcab Registered User Join Date: Apr 2012 Location: Chatt Tn Posts: 957	Re: Lost my Blower motor speeds I would check the resistor first, as its easy to get to. you can back probe the plug and see if power is getting thru. the fan switch does go bad sometimes as well but its alot more work to get to. __________________ 88 military v30 crewcab shortbed 5.9 cummins, nv4500, 205 86 k30, 89 diesel burb, 76 gmc pathfinder 71 longbed 5.3 4l80 http://67-72chevytrucks.com/vboard/s...d.php?t=522535

09-14-2023, 09:38 PM	#5
kglowacky Registered User Join Date: Mar 2020 Location: The Woodlands,Tx Posts: 559	Re: Lost my Blower motor speeds agree check resistor 1st

09-15-2023, 03:25 AM	#6
Pontiac1976 Registered User Join Date: Oct 2015 Location: Ottawa, Ontario, Canada Posts: 750	Re: Lost my Blower motor speeds The resistor 1st (burned) out or plug dirty corroded connectors need cleaning. And you may want to check the Gound clean protect. make sure it got 100% good ground. __________________ 1977 REG cab Long Bed with a 1984 Front Clip, 82 305 .60 over 9.0.1 flat top pistons, 4bbl, TH350, w/84 SS-intake & cam , w/ 1977 big block rad, 1975 gear box, 1984 master w/ metric fittings top & SAE fitting @ portion block, 1975 3.42 gear open diff. Duel 77-87 Factory air cleaner, duel inlet from rad support . Down sized 9' to new 8' Steel flat bed Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change.

09-15-2023, 07:28 AM	#7
chrismoore701 Registered User Join Date: Dec 2004 Location: Highland, IN Posts: 2,318	Re: Lost my Blower motor speeds I think I have two (2) plugs on my AC box, but do not see a resistor. Ill look tonight, any pics of where this would be? __________________ Chris _______________________________ 1979 Chevy Stepside SPORT 2018 Chevy Silverado, 39 years apart My build 2008-2016. http://m.imgur.com/a/bURrE

09-15-2023, 08:25 AM	#8
kglowacky Registered User Join Date: Mar 2020 Location: The Woodlands,Tx Posts: 559	Re: Lost my Blower motor speeds you cant see the resistor only the plug without removal. 2 Screws after you unplug it. Looks like a toaster element once you get it out,

09-18-2023, 07:18 AM	#10
chrismoore701 Registered User Join Date: Dec 2004 Location: Highland, IN Posts: 2,318	Re: Lost my Blower motor speeds thanks, will look into that __________________ Chris _______________________________ 1979 Chevy Stepside SPORT 2018 Chevy Silverado, 39 years apart My build 2008-2016. http://m.imgur.com/a/bURrE



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