Heater Blower - 64 C10 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**MikeN** · 12-09-2011, 11:00 AM

The blower fan on my 64 now works only on the highest speed. The motor was replaced a few years ago, and is still quiet and seems to function normally...but only on the highest speed. Is this likely a problem with the blower motor, or could it be the switch? Or something else?

1963c-10 · 12-09-2011, 11:20 AM

I think its your heater switch on the dash. That controls the speed of the blower motor.

Clownpuncher · 12-09-2011, 12:48 PM

Do these trucks have blower motor resistor's that are seperate from the switch? If so I would think it's your resistor. If one is bad it send's full power to motor only allowing the highest setting to be used. Atleast that's what I replace all the time on most cars with the same symptons.

Good luck

1963c-10 · 12-09-2011, 03:11 PM

Yes, the resistor mounts on the heater box inside the cab, should glow red when hot.

**MikeN** · 12-12-2011, 02:53 PM

This is helpful guys, thanks.

**rideblue00** · 12-12-2011, 07:00 PM

Quote:

Originally Posted by 1963c-10

Yes, the resistor mounts on the heater box inside the cab, should glow red when hot.

Could you elaborate on why/what that means? I never knew what that thing was.

markeb01 · 12-12-2011, 10:13 PM

The resistor mounts on the back (firewall side) of the heater ducting. That is most likely what is causing your problem. When the resistor fails, high speed works but slower speeds do not, since power flowing through the resistor is what slows down the fan motor. If you follow the wire loom to the back of the ducting, you should be able to "feel" your way around to unplug the harness from the resistor, and then pop the resistor out of the ducting. It just snaps in place.

It appears however that most of the aftermarket suppliers are only selling the later version which is attached with screws. This may require either modification to fit the spring retainers, or installing it with screws.

Here's a schematic showing where it goes:

**MikeN** · 12-13-2011, 02:33 PM

That is really helpful, thanks!

**LostMy65** · 09-07-2012, 12:40 AM

My resistor on my 66 fell apart.

Classic Parts has them for sale:
http://www.classicparts.com/1960-72-...ctinfo/68-375/

12-09-2011, 11:00 AM	#1
MikeN Senior Member Join Date: Oct 2007 Location: Marietta, GA Posts: 782	Heater Blower - 64 C10 The blower fan on my 64 now works only on the highest speed. The motor was replaced a few years ago, and is still quiet and seems to function normally...but only on the highest speed. Is this likely a problem with the blower motor, or could it be the switch? Or something else?

12-09-2011, 11:20 AM	#2
1963c-10 Registered User Join Date: Nov 2011 Location: fayetteville nc Posts: 10,338	Re: Heater Blower - 64 C10 I think its your heater switch on the dash. That controls the speed of the blower motor. __________________ 1963 Short bed step side SBW 427 big block and borg warner T-16 HD 3 speed manual http://67-72chevytrucks.com/vboard/s...d.php?t=519869 1963 Short bed fleetside BBW 348 1st gen big block w/Powerglide http://67-72chevytrucks.com/vboard/s...d.php?t=619024 1964 Short bed trailer

12-09-2011, 12:48 PM	#3
Clownpuncher Registered User Join Date: Dec 2011 Location: EL Mirage , Az Posts: 55	Re: Heater Blower - 64 C10 Do these trucks have blower motor resistor's that are seperate from the switch? If so I would think it's your resistor. If one is bad it send's full power to motor only allowing the highest setting to be used. Atleast that's what I replace all the time on most cars with the same symptons. Good luck

12-09-2011, 03:11 PM	#4
1963c-10 Registered User Join Date: Nov 2011 Location: fayetteville nc Posts: 10,338	Re: Heater Blower - 64 C10 Yes, the resistor mounts on the heater box inside the cab, should glow red when hot. __________________ 1963 Short bed step side SBW 427 big block and borg warner T-16 HD 3 speed manual http://67-72chevytrucks.com/vboard/s...d.php?t=519869 1963 Short bed fleetside BBW 348 1st gen big block w/Powerglide http://67-72chevytrucks.com/vboard/s...d.php?t=619024 1964 Short bed trailer

12-12-2011, 02:53 PM	#5
MikeN Senior Member Join Date: Oct 2007 Location: Marietta, GA Posts: 782	Re: Heater Blower - 64 C10 This is helpful guys, thanks.

12-12-2011, 10:13 PM	#7
markeb01 Senior Enthusiast Join Date: Feb 2007 Location: Spokane Valley, WA Posts: 8,356	Re: Heater Blower - 64 C10 The resistor mounts on the back (firewall side) of the heater ducting. That is most likely what is causing your problem. When the resistor fails, high speed works but slower speeds do not, since power flowing through the resistor is what slows down the fan motor. If you follow the wire loom to the back of the ducting, you should be able to "feel" your way around to unplug the harness from the resistor, and then pop the resistor out of the ducting. It just snaps in place. It appears however that most of the aftermarket suppliers are only selling the later version which is attached with screws. This may require either modification to fit the spring retainers, or installing it with screws. Here's a schematic showing where it goes: Last edited by markeb01; 12-12-2011 at 10:22 PM.

12-13-2011, 02:33 PM	#8
MikeN Senior Member Join Date: Oct 2007 Location: Marietta, GA Posts: 782	Re: Heater Blower - 64 C10 That is really helpful, thanks!

09-07-2012, 12:40 AM	#9
LostMy65 But Found Her 25yrs Later! Join Date: Oct 2010 Location: Oregon City, Oregon Posts: 10,525	Re: Heater Blower - 64 C10 My resistor on my 66 fell apart. Classic Parts has them for sale: http://www.classicparts.com/1960-72-...ctinfo/68-375/ __________________ I lost my 65 - Found it 25 years later: http://67-72chevytrucks.com/vboard/s...d.php?t=426650 66 C20 Service Truck: http://67-72chevytrucks.com/vboard/s...d.php?t=428035



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