Jalopy
Full Access Member
- Joined
- Oct 31, 2021
- Posts
- 58
- Reaction score
- 27
- Location
- manteca california
- First Name
- joe
- Truck Year
- 1973
- Truck Model
- k10
- Engine Size
- 383 stroker
It won't turn off, anyone know why?
Blower motor wont turn off
- Thread starter Jalopy
- Start date
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.
Rickf
Full Access Member
- Joined
- Jul 29, 2017
- Posts
- 567
- Reaction score
- 708
- Location
- Grafton NH
- First Name
- Rick
- Truck Year
- 1974, 1954 & a 1937
- Truck Model
- K20
- Engine Size
- 350
Some year squares are always on low. Is "off" missing from the heater/defroster control?
75gmck25
Full Access Member
- Joined
- Oct 13, 2016
- Posts
- 2,240
- Reaction score
- 2,166
- Location
- Northern Virginia
- First Name
- Bruce
- Truck Year
- 1975
- Truck Model
- K25 Camper Special TH350 NP203
- Engine Size
- 5.7
Many GM vehicles have a blower motor that runs any time the ignition is on. For our trucks it varies by year, but I know it is continuous-run on my ‘75.
Bextreme04
Full Access Member
- Joined
- May 13, 2019
- Posts
- 4,436
- Reaction score
- 5,559
- Location
- Oregon
- First Name
- Eric
- Truck Year
- 1980
- Truck Model
- K25
- Engine Size
- 350-4bbl
Any square 1980 and earlier will not have an "off" setting for the blower. It will always run at least a little bit.
gotyourgoat
Full Access Member
- Joined
- Mar 27, 2014
- Posts
- 2,117
- Reaction score
- 3,418
- Location
- NRV Virginia
- First Name
- gotyourgoat
- Truck Year
- 1984
- Truck Model
- c10
- Engine Size
- smokin' 305
Used to have a scan of an old GM advertisement touting this feature, since lost to a broken phone. They called it their constant cabin ventilation or something similar. It was across many if not all models, not just trucks.
I've heard a few times it was because of a lawsuit gm lost where some people died of asphyxia while sitting in running parked vehicles. Maybe Gm scrubbed this from the interwebs because I cannot seem to confirm that is indeed what brought constant cabin ventilation into our lives.
You could always just pull the one plug out of the heater box and make it always off.
AuroraGirl
Full Access Member
- Joined
- Sep 8, 2019
- Posts
- 9,693
- Reaction score
- 6,862
- Location
- Northern Wisconsin
- First Name
- Taylor
- Truck Year
- 1978, 1980
- Truck Model
- K10, K25
- Engine Size
- 400(?), 350
You must be registered for see images attach
I think the complicated "air" system this car had makes sense now with that blower motor thing running all the time, there is the valves under dash on the left and the upper switch on the left and the heater stack says off, but its a 75 so maybe that was there way around it
AuroraGirl
Full Access Member
- Joined
- Sep 8, 2019
- Posts
- 9,693
- Reaction score
- 6,862
- Location
- Northern Wisconsin
- First Name
- Taylor
- Truck Year
- 1978, 1980
- Truck Model
- K10, K25
- Engine Size
- 400(?), 350
xc_hide_links_from_guests_guests_error_hide_media
Terry Wilkerson
Full Access Member
- Joined
- Dec 2, 2021
- Posts
- 505
- Reaction score
- 678
- Location
- Kansas
- First Name
- Terry
- Truck Year
- 1986
- Truck Model
- GMC 1500
- Engine Size
- 350
My 86 gmc the off is on the ac Def heat selector side. Off is all the way to the left.
AuroraGirl
Full Access Member
- Joined
- Sep 8, 2019
- Posts
- 9,693
- Reaction score
- 6,862
- Location
- Northern Wisconsin
- First Name
- Taylor
- Truck Year
- 1978, 1980
- Truck Model
- K10, K25
- Engine Size
- 400(?), 350
1980 ad (not disputing terry just found thread in notifications )
You must be registered for see images attach
SirSmartyPants
Junior Member
- Joined
- Apr 4, 2024
- Posts
- 17
- Reaction score
- 52
- Location
- Northern Virginia, USA
- First Name
- Ron
- Truck Year
- 1974
- Truck Model
- C10
- Engine Size
- 350
Has anyone successfully rigged a switch/relay in one of these models, such that when the Off/Def/Heat selector is all the way left (Off) it turns off the blower motor?
AuroraGirl
Full Access Member
- Joined
- Sep 8, 2019
- Posts
- 9,693
- Reaction score
- 6,862
- Location
- Northern Wisconsin
- First Name
- Taylor
- Truck Year
- 1978, 1980
- Truck Model
- K10, K25
- Engine Size
- 400(?), 350
It would be easier to just wire an on-off and mount it to the original face plate.
I didnt realize the motor being on with key on was an intentional thing before 1982-1984, so I put a switch inline the (I think) purple wire to the wiper speed switch, because I didnt want it running all the time. I dont have a faceplate, so it just hangs there.
SirSmartyPants
Junior Member
- Joined
- Apr 4, 2024
- Posts
- 17
- Reaction score
- 52
- Location
- Northern Virginia, USA
- First Name
- Ron
- Truck Year
- 1974
- Truck Model
- C10
- Engine Size
- 350
I thought about doing that, too. In fact, I ordered a switch for the purpose before deciding I didn't want to cut holes in my dash. I have a relay, and I've ordered a limit switch with a lever. I plan to mount the switch to the plate in the ventilation control unit so that it opens the circuit to the fan when the lever is in the Off position. I'll post pics if/when I get it working.
AuroraGirl
Full Access Member
- Joined
- Sep 8, 2019
- Posts
- 9,693
- Reaction score
- 6,862
- Location
- Northern Wisconsin
- First Name
- Taylor
- Truck Year
- 1978, 1980
- Truck Model
- K10, K25
- Engine Size
- 400(?), 350
You must be registered for see images attach
you could also just switch over to the wiring/electrical from a 1982 or newer square. I think, but i could be wrong, the necessary electronics are contained in the switch and maybe the harness from the switch to where it all runs to
EvilGenius
Full Access Member
- Joined
- May 12, 2016
- Posts
- 203
- Reaction score
- 152
- Location
- Metro Detroit
- First Name
- Darien
- Truck Year
- 1983
- Truck Model
- K10
- Engine Size
- 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.
