Blower Control Module.
Thread Starter
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
Blower Motor Resistor.
What exactly does the Blower Motor Resistor that's mounted on top of the evaporator housing do?
I have a 91 Vette and I just noticed that the connector was on incorrectly leaving one of the spade terminals disconnected. Everything seems to be working good Heat, Vent, Defrost, Blower Fan and AC functions all work Great. (Vette has Manual AC/Heat controls).
I reconnected the connector and everything is still good. Just wondering what it's purpose was?
Here's a picture.
I have a 91 Vette and I just noticed that the connector was on incorrectly leaving one of the spade terminals disconnected. Everything seems to be working good Heat, Vent, Defrost, Blower Fan and AC functions all work Great. (Vette has Manual AC/Heat controls).
I reconnected the connector and everything is still good. Just wondering what it's purpose was?
Here's a picture.
Last edited by GKK; Nov 8, 2010 at 04:09 PM.
Thread Starter
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
I found this on the Internet:
"A blower motor resistor is the device by which a car's heating and air conditioning unit controls the fan speeds."
How does this "Resister" control the fan speed on a "Manual" Heater/AC Blower system?
"A blower motor resistor is the device by which a car's heating and air conditioning unit controls the fan speeds."
How does this "Resister" control the fan speed on a "Manual" Heater/AC Blower system?
Last edited by GKK; Nov 8, 2010 at 04:23 PM.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
It's used to control the source voltage (battery/alternator in an automobile) so that the output for a given selection is always the same. Resistance or the Resistor simply blocks/reduces the voltage so the output is less. For most motor or electrical circuits, you want as little resistance as possible. For the blower motor however, it's being used to control the speed of the motor. With greater resistance, less voltage reaches the motor, so it runs slower; with less resistance, it gets more of the potential and runs faster. On the high or max side, because the source can vary with battery charge and alternator output, it's being used to max out the source at somewhere around 12 volts. That way, the Blower Motor doesn't speed up or slow down with the output of the alternator, though it will slowdown if it drops below battery.
