75 K5...Is the fan always on?

[Cheyenne75]

Just got this last week 75 K5 noticed the fan on very low with all switches in the off position is that stock on the rig or maybe a new switch is needed did a search on the wiring everywhere before I asked can't seem to narrow it down..Many Thanks

 

[Snoozer]

I have the exact same issue on my '76 K10.

So I'm hoping someone chimes in.

 

[7T4]

My 74 K5 does it as well.

 

[dyeager535]

Factory setup.

 

[tRustyK5]

Yup, it's intentional. I think GM called it "flow through ventilation" or something similar.

 

[Cheyenne75]

Thanks fellas,

I'm going through the rig heard the fan though I would give it a gallant effort before I asked, works as it should from GM is always great news

 

[diesel4me]

Yup,GM designed the "flow thru ventilation" in their cars and trucks in the 70's,they added lovered vents in the doors and cab at the jambs and made the heater blower motor always run on low speed in most of them,even with the switch in the off position...
....if it annoys you to have it running constantly,as a few of mine did ,(they would screech horribly on frigid mornings on low speed!),I cured that by snipping the wire on the blower motor resistor that powers the low speed setting...then "off" really IS "off"!...and you still have medium and hi speed ...

 

[Cheyenne75]

Yup,GM designed the "flow thru ventilation" in their cars and trucks in the 70's,they added lovered vents in the doors and cab at the jambs and made the heater blower motor always run on low speed in most of them,even with the switch in the off position...
....if it annoys you to have it running constantly,as a few of mine did ,(they would screech horribly on frigid mornings on low speed!),I cured that by snipping the wire on the blower motor resistor that powers the low speed setting...then "off" really IS "off"!...and you still have medium and hi speed ...

I will be hunting for that wire and off will be off...you called it I live in the snow and sure nuff she screechs at sub-zero temps..wire dykes here I come. Thanks Diesel

 

[folkenheath]

Just swap the main switch in the control board to one with an off position. I got one from a parts truck and it works fine.