I'm looking into a dvd/gps/lcd/etc aftermarket unit in place of my aging EL cassette deck.

I've been trying to find info about how radio steering wheel controls work, but AFAICT all they are is a wire with different value resistors connected to each button.
AFAIK the AU uses the same steering wheel as EL, and the EL even has a spare hole in the steering wheel that the AU uses for its radio 'data' line, but it doesn't have a wire whereas the AU does.

This is what I know about the EL's cruise controls:
* It consists of 3 wires - the two horn wires (black, blue) plus an additional cruise 'data' wire (orange + yellow)
* I'm assuming the black wire is ground and the blue wire is +V (not sure what voltage)
* Shorting the data wire to blue will turn cruise on and shorting it to black will turn cruise off
* The cruise buttons each use a resistor to connect the data wire to the black wire, and consist of Coast (2200ohm), Set+ (680ohm), and Set- (120ohm)
* Since the AU uses different resistor values, to use AU controls you need to open up he buttons and change the resistors to match the EL values

...Anyway, my question is this: could I use the AU cruise and radio controls on an EL steering wheel (assuming I change the resistor values and relocate the cruise on/off switch), and would sending unknown radio resistor values down the cruise data line affect the cruise module or any other car electronic devices at all?. I would try and pick values that don't match any combinations of buttons that might confuse the cruise control (the unit I'm looking at can be trained to learn the buttons and I assume ignore the cruise values). Any suggestions of resistor values to use for up to 6 radio buttons? (I plan to include additional tiny buttons for bluetooth/etc on the rear side of the radio buttons)

Thanks in advance.

I believe the cruise unit is the same/different programming across ef -> AU.

So.. you'll probably find you'll be ok. Why not give it a go anyway!.

You should actually be able to modify the AU Switches into your EF (If they dont already just bolt up) so you can use the AU on/off switch as well.

Nigel

If you use the AU clockspring, and some of the steering wheel button wiring, and I think the air bag may be needed; you can set it all up as per factory.

You will have to look up the info yourself, I don't remember where it is, all I know is its been done before. Good luck.

I was actually suggesting keep the EF/L clockspring, and switch base, but replace the switches with EF/L ones.

I did that on my XF (dont laugh) - EF Steering Column, EF Switch base with EB Switches (ok, I like the EB Stuff better, but wanted the clockspring for cruise control in my XF.. it has a 5.0 EFI in it)