Blower fan motor no A/C
 

I just replaced my blower fan motor in the 79, it started squealing like a pig in the cold. The thread about missing blower motor resistor got me thinking. Is this blower motor a 3 speed or 2 speed motor? I sprayed out plug to resistor because it was pretty dirty. Well when I cleaned it the fan motor only comes on 2 speed low and high. In low speed the new motor wines a little. When I turn radio on does not really bother me. I was just wondering if I go back to parts store and try and see if I can get a quieter one or if all fan motors in low sound this way.
Thanks

Re: Blower fan motor no A/C
 

I have replaced a few due to squealing so I would return for exchange. Be sure you have a good motor ground. Sometimes the ground wire that normally connects to fan housing may not be good there. Move to a proper location to insure good ground. Next I would check the resistor, it may be bad. Check fuses too. I'm not sure about motor speed being 2 or 3. The resistor determines that. Mine is a 4 speed w/ac.

Re: Blower fan motor no A/C
 

All the GM blower motors I know of from the square era don't have speeds. They are a simple one power wire setup. The different speeds are made by the resistor setup(and maybe a relay) + fan switch that supplies different voltages to the motor.

The motor itself should be mostly quiet at all speeds. You will get a fair amount of moving air noise.

That last time I had to replace a blower, it took a couple tries to get a quiet one. QC seems a lost art on vehicle parts.

Re: Blower fan motor no A/C
 

AC and non AC blowers are wired differently.

The blower on the AC systems has three positions through the resistor and HI is routed through the blower relay on the AC box.

The non AC systems have two positions through the resistor and HI is direct to the motor.

Are you getting RF motor noise on the radio or the fan itself is squealing mechanically?

Re: Blower fan motor no A/C
 

No RF interference luckily just like a whirling noise in low position. If for some reason the radio stopped working and I had to just listen to fan motor on low speed it might get annoying. I might try and get another fan motor when it warms up in the spring time and replace since it is a lifetime warranty part. It is a little too cold in CO right now to mess with it, I am just glad it keeps truck warm and does not squeal on start up. I am sure the neighbors appreciate that.
So just to be clear on non-ac cars the switch is off-low-high, is that correct