Thanks for the reply. Basically what I'm trying to do is install steering wheel controls in my Chrysler 300 which currently does not have any. A person on a different forum achieved this by purchasing a steering wheel control interface which allows you to retain your steering wheel controls with an after market head unit. On the forum he says the interface (PAC SWI-RC) can interpret the values from the resistors but in order to do this he had to solder some resistors of different values to the buttons, he did not go into any further detail. I had read on the SWI-RC manual that some vehicles have separate wires for each button and sometimes resistors need to be soldered to each wire in order for the interface to recognize them and I assumed this would basically be the same thing. Like I said I am new to all of this and I don't know exactly where to solder these resistors. I'm sorry for being so vague I should of went into more detail before but your help is greatly appreciated.
That helps a great deal.
As you said, some controls have a different wire for each button, other use resistors...
There will be two major hurdles for you though, and I doubt we can help with them.
First and foremost, I forget what the part is called, but it allows the wires to be ran up the steering wheel column AND rotate with the wheel. It is in the shape of a collar with wires in and wires out. This colar will be split in two parts, and one part will rotate with the steering wheel, the other will stay stationary. If your vehicle did not come with steering controls then you are most likely missing this part. Without this part you will need to rely on something battery powered and wireless.
Second hurdle... Resistors range in a large number of values.... here is a link to the more standard values :
http://ecee.colorado.edu/~mcclurel/resistorsandcaps.pdf
Please note that there are many many more 'precision' values. Additionally, the control could be reading one of two things...
Voltage, current, and resistance all work together.... This means that when a resistor is energized, there will be a different voltage on one side compared to the other... I am unsure if the controls are actually measuring the resistor, or if they are measuring the difference in voltage that the resistor has now created. To make matters trickier... without knowing what the stereo is expecting, we cannot even begin to guess what kinds of combinations the resistors must be to make this function.
If we were designing from scratch this would be different. As we could dictate the values. We are attempting to talk to an existing system, we need some specifications on how to do so.
Just to clarify... do you have a stock stereo, and are adding an aftermarket steering wheel control?