Blower motor wont turn off

EvilGenius said:

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.

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Prob have a bad relay or something
1982 the feature to turn off the fan came out.

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.

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.

SirSmartyPants said:

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.

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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

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?

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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.