Blower motor has one speed: "On" - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kcackler · 04-26-2009, 11:34 PM

This isn't really a problem, but rather just a curiosity thing. The fan speed on my Air conditioning/heater controls does absolutely nothing. The fan is always running so long as the truck is on (Which I understand is normal operation), but I cannot turn the fan speed up or down.

Just curious if this could be something simple. I plan on adding A/C back into the truck this summer (All the parts are there..just got to make them work) and would like to get this fan thing fixed as well.

flamingbig10 · 04-26-2009, 11:37 PM

I would first check all of the wiring connection and grounds

gchemist · 04-27-2009, 02:31 AM

Pull the plug on the fan. Test for power. If it has power the ground is not working. Check the resistor. Next check for power at the relay. If there is no power at the relay, check for power at the switch.

Damien · 04-27-2009, 01:57 PM

Since it does not change speeds, I would think it is the fan switch.

Prong · 04-30-2009, 03:03 AM

I had this happen to me a couple of months ago. Turned out to be the resistor. $12 later everything was right again.

Tony@AirRideTech · 04-30-2009, 10:26 AM

I am thinking fan switch too........ when it is turned OFF it should not be getting any power.

84lwb · 04-30-2009, 05:08 PM

hate to hijack but mine does does just the opposite NOTHING.mind you the vac. line is not hooked up but I have no fan at all.again sorry for the hijack.

setelec 73 · 04-30-2009, 07:14 PM

Just a heads up. I am having the same problem on my 73.. I have now changed the blower motor, resistor, relay and switch and am still having the problem. The new switch actually has only 4 prongs instead of 5 like the original. The original had 2 plugs that went into it. The fifth prong had a single wire to it. Is this something that is no longer needed?? I will let you know when I finally fix the problem!! It is driving me crazy!!! Hopefully we can get some more help from the experts on the site..

04-26-2009, 11:34 PM	#1
kcackler Registered User Join Date: Feb 2009 Location: Russellville, AR Posts: 164	Blower motor has one speed: "On" This isn't really a problem, but rather just a curiosity thing. The fan speed on my Air conditioning/heater controls does absolutely nothing. The fan is always running so long as the truck is on (Which I understand is normal operation), but I cannot turn the fan speed up or down. Just curious if this could be something simple. I plan on adding A/C back into the truck this summer (All the parts are there..just got to make them work) and would like to get this fan thing fixed as well. __________________ Blue - 77 Chevy Scottsdale

04-26-2009, 11:37 PM	#2
flamingbig10 6.0 powered square Join Date: Feb 2008 Location: Mesquite texas Posts: 3,459	Re: Blower motor has one speed: "On" I would first check all of the wiring connection and grounds __________________ Aaron 1980 c-10 short bed lowered, cammed 6.0, 4l80e 3600 stall, smp tune, wilwoods, and flames best time so far best et 7.86 @87 on motor 7.57 90 on a 75 shot Build http://67-72chevytrucks.com/vboard/s...d.php?t=283326

04-27-2009, 02:31 AM	#3
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: Blower motor has one speed: "On" Pull the plug on the fan. Test for power. If it has power the ground is not working. Check the resistor. Next check for power at the relay. If there is no power at the relay, check for power at the switch. __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

04-27-2009, 01:57 PM	#4
Damien Registered User Join Date: Mar 2007 Location: Farmington, MN Posts: 928	Re: Blower motor has one speed: "On" Since it does not change speeds, I would think it is the fan switch. __________________ I can still count my vehicles on two... wait three hands.

04-30-2009, 03:03 AM	#5
Prong Registered User Join Date: May 2007 Location: CO Posts: 475	Re: Blower motor has one speed: "On" I had this happen to me a couple of months ago. Turned out to be the resistor. $12 later everything was right again.

04-30-2009, 10:26 AM	#6
Tony@AirRideTech Junior Member Join Date: Feb 2005 Location: Huntingburg IN Posts: 620	Re: Blower motor has one speed: "On" I am thinking fan switch too........ when it is turned OFF it should not be getting any power.

04-30-2009, 05:08 PM	#7
84lwb Registered User Join Date: Apr 2007 Location: Southern Maryland Posts: 209	Re: Blower motor has one speed: "On" hate to hijack but mine does does just the opposite NOTHING.mind you the vac. line is not hooked up but I have no fan at all.again sorry for the hijack.

04-30-2009, 07:14 PM	#8
setelec 73 Registered User Join Date: Apr 2009 Location: Los Angeles, CA Posts: 78	Re: Blower motor has one speed: "On" Just a heads up. I am having the same problem on my 73.. I have now changed the blower motor, resistor, relay and switch and am still having the problem. The new switch actually has only 4 prongs instead of 5 like the original. The original had 2 plugs that went into it. The fifth prong had a single wire to it. Is this something that is no longer needed?? I will let you know when I finally fix the problem!! It is driving me crazy!!! Hopefully we can get some more help from the experts on the site..



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