Blower Motor only works on Med - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**pound41** · 12-15-2014, 12:23 PM

Hello:
I bought this 71 blazer with A/C about a year ago. blower motor only worked on medium. I replaced the relay up by the kick panel it all worked great. This year goes back to only working on medium. I have replaced the relay again, blower motor and switch. Still no change. What else can it be.
Thanks

MARKDTN · 12-15-2014, 12:25 PM

Resistor pack.

**leddzepp** · 12-15-2014, 12:29 PM

Check the ground on the relay. I had the same problem you describe and that was the culprit.

**pound41** · 12-15-2014, 01:55 PM

I will check the ground on the relay
if it is the resistor pack where is it located
Thanks

mrein3 · 12-15-2014, 02:13 PM

I bet the switch or the plug behind the switch is fried.

I converted my truck to AC. When doing that, I discovered that EVERY used blower motor switch I found in the junk yard was not working and the plastic plug that plugs in the back of the switch was melted. I ordered a new switch, new plug, and ran all new wires with the correct color and gauge according to the wiring diagram.

That was about 10 years ago.

Fast forward to last winter. My blower didn't work on one or two speeds. Sure enough my brand new plastic plug was fried. Again. And it took the switch out. Again.

I was in a hurry so I ordered a couple of new switches and a couple new plugs, replaced them, and put on my list of things to do "find orange, yellow, light blue, and brown wire in 12 gauge."

Stock wire is 14 gauge. Obviously it isn't beefy enough.

Anybody know where I can find light blue stranded 12 gauge wire? The other three colors are easy to find.

MARKDTN · 12-15-2014, 04:12 PM

Quote:

Originally Posted by pound41

I will check the ground on the relay
if it is the resistor pack where is it located
Thanks

http://67-72chevytrucks.com/vboard/s...d.php?t=532916

12-15-2014, 12:23 PM	#1
pound41 Registered User Join Date: Dec 2002 Location: Northern Virginia Posts: 1,268	Blower Motor only works on Med Hello: I bought this 71 blazer with A/C about a year ago. blower motor only worked on medium. I replaced the relay up by the kick panel it all worked great. This year goes back to only working on medium. I have replaced the relay again, blower motor and switch. Still no change. What else can it be. Thanks

12-15-2014, 12:25 PM	#2
MARKDTN Registered User Join Date: Jan 2011 Location: Chattanooga, TN Posts: 2,159	Re: Blower Motor only works on Med Resistor pack. __________________ '83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project

12-15-2014, 12:29 PM	#3
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 20,019	Re: Blower Motor only works on Med Check the ground on the relay. I had the same problem you describe and that was the culprit. __________________ 1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man RIP FleetsidePaul

12-15-2014, 01:55 PM	#4
pound41 Registered User Join Date: Dec 2002 Location: Northern Virginia Posts: 1,268	Re: Blower Motor only works on Med I will check the ground on the relay if it is the resistor pack where is it located Thanks

12-15-2014, 02:13 PM	#5
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,253	Re: Blower Motor only works on Med I bet the switch or the plug behind the switch is fried. I converted my truck to AC. When doing that, I discovered that EVERY used blower motor switch I found in the junk yard was not working and the plastic plug that plugs in the back of the switch was melted. I ordered a new switch, new plug, and ran all new wires with the correct color and gauge according to the wiring diagram. That was about 10 years ago. Fast forward to last winter. My blower didn't work on one or two speeds. Sure enough my brand new plastic plug was fried. Again. And it took the switch out. Again. I was in a hurry so I ordered a couple of new switches and a couple new plugs, replaced them, and put on my list of things to do "find orange, yellow, light blue, and brown wire in 12 gauge." Stock wire is 14 gauge. Obviously it isn't beefy enough. Anybody know where I can find light blue stranded 12 gauge wire? The other three colors are easy to find. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN



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