Blower motor wont turn off

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,693
Reaction score
6,875
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
It runs constantly in my 83 k10 with an 85 interior harness. The off position is slower than Low, but it still runs. I only drive my truck in the summer so I just unplugged the harness from the blower resistor on the firewall. If I ever want heat a couple minutes plugging it back in is all it takes.
Prob have a bad relay or something
1982 the feature to turn off the fan came out.
You must be registered for see images attach
 

EvilGenius

Full Access Member
Joined
May 12, 2016
Posts
205
Reaction score
159
Location
Metro Detroit
First Name
Darien
Truck Year
1983
Truck Model
K10
Engine Size
350
The way I'm reading that seems to mesh with what I said. Power ventilation seems to say that there is some blower movement. Or maybe not. Marketing speak is never straight forward. I'm curious if anyone else experience matches mine. All I know is it is a lot cooler in the cab with it unplugged. I can't move my deflector valve in the heater box because I tried to replace the foam inside it with cheap crap. The adhesive came off just enough for it to block the blend door and now it won't move. And taking it off to fix it when I don't really use it is such a pain.
 

SirSmartyPants

Junior Member
Joined
Apr 4, 2024
Posts
18
Reaction score
52
Location
Northern Virginia, USA
First Name
Ron
Truck Year
1974
Truck Model
C10
Engine Size
350
Here’s my solution to it (74 C10). It’s a micro limit switch, mounted so that the Off/Heat/Defrost selector presses the switch lever and opens the circuit when it’s in the Off position. This will be wired to a relay to provide power to the blower motor when the lever is moved to Heat or Defrost.
You must be registered for see images attach
You must be registered for see images attach
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,693
Reaction score
6,875
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
Here’s my solution to it (74 C10). It’s a micro limit switch, mounted so that the Off/Heat/Defrost selector presses the switch lever and opens the circuit when it’s in the Off position. This will be wired to a relay to provide power to the blower motor when the lever is moved to Heat or Defrost.
You must be registered for see images attach
You must be registered for see images attach
I had to replace a limit switch on 2 riveter machines at work. My smaller hands and mechanical knowledge apparently made me the person for the job. Had to trim the lever and fish it in just right so it actuates properly for the safety mechanism. So when the anvil comes down, anyones hand in the area stops a wire guard which then presses the micro switch so the anvil will immediately stop and reverse
So if I understand you right, you want it to be in contact with the switch for function of your HVAC, but when let off it cuts the power?

Depending on how much you use your hvac, you may want to reverse the roles , if you know what I mean? Do you have AC? A manual hvac truck with the floor vents and vent windows may not use the system much, but if you got AC you may
 

SirSmartyPants

Junior Member
Joined
Apr 4, 2024
Posts
18
Reaction score
52
Location
Northern Virginia, USA
First Name
Ron
Truck Year
1974
Truck Model
C10
Engine Size
350
So if I understand you right, you want it to be in contact with the switch for function of your HVAC, but when let off it cuts the power?
No, the other way around. It cuts the power when the lever is depressed. It doesn’t have AC, so 90% of the time it will be off, and I doubt it will see very many cycles.
 

Forum statistics

Threads
44,414
Posts
957,079
Members
36,750
Latest member
jdishman2355
Top