The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Electrical

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-01-2020, 09:52 PM   #1
57taskforce
All about them K’s
 
57taskforce's Avatar
 
Join Date: Jun 2014
Location: Farmington, New Mexico
Posts: 6,221
No power to blower motor.

I’ve read several threads trying to diagnose my issue with no success. I can’t get power to the purple motor feed. 72K20 with factory AC.
I’ve got power to the switch, the relay clicks when I switch it off of high speed, I’ve got power to the blue wire at the relay and the small orange stand alone wire on the relay.
I’ve got power to the double yellow wires on the resistor.
All of this and I’ve got no power to the blower motor as verified with a multi meter and test light both (grounded to the negative batter terminal) on the purple motor feed wire.
Is my resistor bad and relay both bad?? I’m pretty good with electrical stuff but I can’t seem to make heads or tales of this.
Any suggestions?
__________________
Tyler
'57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888
'72 K20 Cheyenne http://67-72chevytrucks.com/vboard/s...d.php?t=662879
‘69 K10 SWB http://67-72chevytrucks.com/vboard/s...d.php?t=805206
'98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's
‘87 IROC-Z all original 50K mile survivor TPI 305 IROC Blue
‘10 Camaro 2SS/RS Aqua Blue Metallic #93 -version 2.0
57taskforce is offline   Reply With Quote
Old 07-02-2020, 03:19 PM   #2
Richard
Senior Member
 
Join Date: Dec 1999
Location: Southern California
Posts: 2,692
Re: No power to blower motor.

Need to rule out the mechanical devices. Seeing as you have a multimeter I would disconnect wires from resistor and ohm it out. Apply 12v to the coil on the relay and ohm it out as well. If the switch is older may want to check that as well.
__________________
Richard
1972 K10 Custom Deluxe SWB Fleetside
My build https://67-72chevytrucks.com/vboard/...d.php?t=800746
Richard is offline   Reply With Quote
Old 07-02-2020, 07:02 PM   #3
dmjlambert
Senior Member
 
dmjlambert's Avatar
 
Join Date: Apr 2016
Location: Cypress, TX
Posts: 3,561
Re: No power to blower motor.

The 12 gauge Orange wire at the relay should have power, because it should be plugged into the fuse box face. Usually plugged in the CIG position. When the relay is energized because you have the switch in high position (all the way down), the relay contacts connect 12 gauge wire to the 12 gauge purple wire. The resistors and other stuff are bypassed.
dmjlambert is offline   Reply With Quote
Old 07-02-2020, 11:28 PM   #4
57taskforce
All about them K’s
 
57taskforce's Avatar
 
Join Date: Jun 2014
Location: Farmington, New Mexico
Posts: 6,221
Re: No power to blower motor.

Thanks guys. I didn’t have any time today to work on it as my wife had me doing honey do’s. I’ll check the orange wire at the fuse box tomorrow. I’m sure it’s something simple. Richard, about the only other thing I haven’t done is to ohm everything out as I ran out of light yesterday evening. I’ll got that tomorrow as well. My Fluke has been getting a workout the last couple days.
__________________
Tyler
'57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888
'72 K20 Cheyenne http://67-72chevytrucks.com/vboard/s...d.php?t=662879
‘69 K10 SWB http://67-72chevytrucks.com/vboard/s...d.php?t=805206
'98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's
‘87 IROC-Z all original 50K mile survivor TPI 305 IROC Blue
‘10 Camaro 2SS/RS Aqua Blue Metallic #93 -version 2.0
57taskforce is offline   Reply With Quote
Old 07-04-2020, 01:02 AM   #5
57taskforce
All about them K’s
 
57taskforce's Avatar
 
Join Date: Jun 2014
Location: Farmington, New Mexico
Posts: 6,221
Re: No power to blower motor.

I got some more time to play with it today and I finally was able to get power to the purple motor feed wire. The orange wire that feeds the fan relay wasn’t making good connection. After all that... the damn blower motor is bad lol. I got to get some parts coming.
__________________
Tyler
'57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888
'72 K20 Cheyenne http://67-72chevytrucks.com/vboard/s...d.php?t=662879
‘69 K10 SWB http://67-72chevytrucks.com/vboard/s...d.php?t=805206
'98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's
‘87 IROC-Z all original 50K mile survivor TPI 305 IROC Blue
‘10 Camaro 2SS/RS Aqua Blue Metallic #93 -version 2.0
57taskforce is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 12:49 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com