[mike69ss]

For a 69 non-A/C Chevelle is the heater blower speed controlled by the resister? I’ve just rewired the car and I’m running test. The blower motor does come on when the level on the dash is moved, but I do not see how to control speed. How does the blower motor control circuit work?

Thanks,

Mike

 

[John_Muha]

There's a couple of wire-wound resistors that mount on the heater box. They are installed in the air stream to try and cool them. These resistors lower the voltage to the fan motor and make it run slower. In high speed mode the motor doesn't go through the resistors so the motor gets a full 12 volts.

 

[mike69ss]

Thanks,

Does that mean that if the resistors are cold the fan stops? Does only the fan level control the fan or does the heat setting effect anything?

 

[John_Muha]

“Does that mean that if the resistors are cold the fan stops?”

No, The resistors are coils of wire made out of a wire similar to a toaster wire. They get real warm when they are used. By putting them in the air steam they are cooled. This keeps them from burning up in a very short time. Hot or cold they work the same.

“Does only the fan level control the fan or does the heat setting effect anything?”

Just the high to low fan speed switch affects the fan speed. This switch selects which resistor or bypasses the resistors and controls fan speed.

 

[chevellefreak1971]

Sorry to invade, but I have a 71 Chevelle that was A/C and I converted it to heat and defrost. I am trying to get that resistor that controls the fan speed. Does any one have a part # or know were I can get one? Thanks for any help and again sorry to invade the conversation.

 

[mike69ss]

Matt

I got the resistor at OPG, but you may be able to get it at NAPA. I can look into getting a 69 part number if that helps.

John,

My fan control is labeled on/off. The fan comes on when the level is all the way over to the right. The fan is not on for most of the levers travel. Sorry that I'm taking so long to understand things -- thanks for your patience

Mike

 

[John_Muha]

We might be talking about 2 different switches. You should have a fan speed selector switch that increases or decreases the fan speed. There’s also a temperature control lever that goes side to side. On an A/C car: “Whenever the temperature control lever is set to Cold or HOT fan will run in the LOW speed in the switch OFF position“. I’m assuming that on a heat only car, the fan will also run on LOW speed when the lever is in the HOT position.

 

[mike69ss]

I found this image on e-bay. It shows the same control panel as my car.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33545&item=2427450894

I do not know how to add a picture to the post.

 

[John_Muha]

Ok, but it's the blower switch that increases or decreases the fan speed.