Air blows even when off

[sierra1500]

So my air blows out of all vents even when turned off. Truck has brand new blower motor and blower motor resistor. The weird thing is when I'm out of freon it doesn't do this. It also sometimes makes weird noises that sound like they're coming from behind the radio or somewhere in that area. I was thinking of replacing the whole climate control station that's right below the radio. Please let me know your suggestions!

Truck:
1995 GMC c1500 Sierra SLE Extended Cab 5.7L V8

 

[johnckhall]

Not an AC expert, but it happened twice in a Ford sedan that I had and it was was the blower motor relay switch (I think????). Maybe be you got a bad resistor??? Was it AC Delco or cheaper knock-off?

 

[sierra1500]

It did this even before the new parts. I only bought the new parts because it randomly started only blowing on high one day, and those parts fixed that. Where is the blower motor switch? Sorry if dumb question, I'm not much of a mechanic lol.

 

[johnckhall]

It did this even before the new parts. I only bought the new parts because it randomly started only blowing on high one day, and those parts fixed that. Where is the blower motor switch? Sorry if dumb question, I'm not much of a mechanic lol.

Not sure on these models. I had to YouTube how to change it on the car I had. I edited my previous post. It was was the blower motor RELAY switch I had to replace.

 

[east302]

Just to clarify, the blower is on despite the fan switch being off?

The fan knob is installed on the blower switch and can be replaced independent of the entire control panel. If the wiring harness connector is melted, that can cause erratic blower operation. That can also be replaced. 1995 was a one-off year for some things so I’m unsure if it is the same, but for 96+ this is the connector, #12064998:

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