Heater blow problem

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Dec 16, 2008 | 02:51 PM

jb10

Thread Starter

Senior User

Joined: Jun 2008

Posts: 383

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From: Aurora CO

Heater blow problem

Hey guys. It's been awhile since I have been logged on here.
Any way it's below 0 in Colorado and I am having a heater problem.
The blower only seems to blow on one speed, low.
The blower is working but it only blows on low no matter what I change the fan speed setting to.
Btw this is on a 78 F150 4x4 with a/c.

I searched but didn't find anything with this same problem.
Thanks in advance for the help.

Dec 16, 2008 | 03:12 PM

firstonraceday

Laughing Gas

Joined: Dec 2000

Posts: 781

Likes: 18

From: East Texas

Sounds like the blower motor resistor. Not sure on a/c equipped trucks, but on mine without a/c, it's located in the ductwork under the dash on the passenger side. It has wiring plugged into it and a couple of screws holding the resistor into the ducting.

Dec 16, 2008 | 03:17 PM

bucks77ford

Post Fiend

Joined: Jan 2006

Posts: 5,037

Likes: 9

From: Kasson, Minnesota

I was thinking the same thing. You can see in this pic where the resister is on the ductwork.

Dec 16, 2008 | 03:36 PM

IowaHighBoy

Freshman User

Joined: Oct 2008

Posts: 49

Likes: 0

That is a GREAT picture...

It does not by chance show where I drill the small hole to spray lube into the Fan or blower Motor.

Thanks for your help!!!
Cedar Rapids, 3" of partly cloudy.

Dec 16, 2008 | 03:38 PM

Alvin in AZ

Postmaster

Joined: Aug 2005

Posts: 2,760

Likes: 8

From: Gadsden Purchase

Quote:

Originally Posted by bucks77ford

I was thinking the same thing.

I was not thinking that. :/
I was thinking your "speed" selector switch is bad.

Don't know '78's setup. :/
On my '75 the hi-contact bypasses the whole resistor pad.

When does the blower run?
...when the selector switch is in any position?
Or what?

Alvin in AZ