heat resistor

I am having a hard time finding the wire diagram to wire this project.

91 ish Chevy Cavalier heater

I am using it in a 74 cj5 for the fan. blower works GREAT! just would like the switch to work. pulled the resistor out and can not figure out how it works. i can not visualize it in my head. does the resistor get power 1st or is the switch power the resistor? 4 wires coming out of block then that is were i get lost.

 

switch should get power first, then on to the resistor, then to the motor. basicaly if it is 3 speed for example, you will have 2 resistors as high speed will be full voltage and not need a resistor, all the switch does is route the full voltage to the low speed resistor and it drops it to say 6volts output, the med speed will route the power to the other resistor, and drop it to say 8volts, and when you are on high it is pretty much straight thru the resistor block at full voltage. this is assuming you dont have a climate controlled setup

 

Some of the heaters I have seen use two resistrors to achieve four fan speeds.

1. full power, no resistor.

2. med/high---lower value resistor

3. med/low --- high value resistor

4. low----both resistors in series.