I picked up a steeringwheel off a 2004 cadillac and have put it on my 92 STS with the hopes of using its switches (vol+ vol- sel+/- etc.). I have started to wire my own controls onto the switches, but in trying to figure out how the switches were wired I have come to suspect that they are actually just resistive, so when you press each button, a different resistance is given, but off the same two wires. This would make sense to cut down on the number of wires that would need to be run through the steering wheel column, but it kind of sucks for my application, as I want distinct buttons.

Can anyone confirm or deny that the buttons would use the same two pins but use different resistance for each?

Yes,

The switch outputs are matrixed thorugh different value resistors and the resistance values are decoded by the BCM (in the original car, obviously your 92 STS will not do this as it was not an availble option on the 92) and then transmitted as commands over the data bus to the appropriate module where the commanded action is carried out.

This is essentially the same system used since 1997 on the Devilles when they added steering wheel controls. You will need some kind of decoder module unless you are resourceful enough to roll your own. One of the audio aftermarket interface adaptor makers has a module that can "learn" resistance value inputs and translate them to infrared outputs. The IR commands are learned from the remote supplied with a headunit and are then retransmitted when triggered by the corresponding steering wheel switch.

If you have an aftermarket head unit with IR remote this would work for you. If you have the factory system, you're outta luck unless you are a world class hardware hacker.

Best of luck!

Kevin

I am actually trying to transmit the signals via a Computer Wireless Gamepad. So I wanted two wires per button. I may just end up custom making some PCB boards with two connectors per button.

What do you think?

Hi guys! I don't mean to "hijack" this thread, but I'm in a very similar situation & Kevin (Kdirk) seems to know alot about these systems.

As my name implies, I've got a '96 STS that has the paddle controls for climate & radio functions and I'm wanting to replace my steering wheel with one from a 2002 that I got off of eBay. I haven't yet started the removal/replacement process, but I did take the switches apart on the '02 wheel & noticed the same thing that you did, jadz. They seem to be resistance "coded".

Kevin, you mentioned that "This is essentially the same system used since 1997 on the Devilles when they added steering wheel controls." Do you think that this would apply to my '96 Seville as well? Will I be able to splice the new switches into the existing wiring & everything will work?

Of course that's what I'm hoping for, but if this is just not going to work, please let me know.

Ultimately, I'm doing this for a wood/leather wheel, but I'd definitely like to keep the controls. Please let me know what my options might be.

Thanks a bunch!

Stephen K.
96 STS

http://www.pac-audio.com/products/swi.htm

this is what you will need provided there are leads on the column that connect to the steering wheel controls.

I use the swi-x for my 97 deville with a pioneer HU

I am either going to try to solder two wires to each push button connection on the PCB and remove them from the resisitive network, or I am going to create my own simple PCB using a kit I picked up at radio shack.

This will give be two buttons per switch which should be nice and simple for my game pad.

- Jadz

up2ng-

Yup, that adaptor you linked to was exactly what I was talking about. I just couldn't find the link or the company name in my bookmarks when I made the post. Good call.

96STS -

To answer your question, yes this is essentially the same system. In fact, the swtiches and steering wheels were the same on the Seville and Deville lines from 1996-1999. I may have been mistaken in saying 1997, the Deville may have had it in 1996 also, but it seems like the Seville was always first to get such enhancements, with the Deville following up a year or two later.

Now, I don't know if the resistance values are the same from 1996 to 2002. I think there are more buttons on the '02 than on the 96, so this may cause a problem as far as a direct match-up. The only way to find this out would be through the service manual (which I unfortunately do not have for either year, I only own a set for my 95 Deville which is different again)

The other problem you may encounter is the air bag being different between the different years. I would be worried about proper deployment of the 2002 airbag when attached to the 1996 column and SIR electronics, that is if you ever have a wreck where the airbag would deploy.

Since you already have a wheel you want to use, this may not be a consideration for you but there is a company that will professionally redo steering wheels with wood and new leather wrap (both with factory matched finish/color) even if they were all leather to start. It isn't cheap (by my recollection around $400-500) but the pictures on their website looked outstanding.

I've considered doing this to mine, I just haven't had the funds yet for such frivolity. I will have to find the link and post it here - if you went this route, you could put your original wheel/airbag/switches back in the car with no worries.

Hope this is of some use to you, I'll post the link when I find it.

Kevin.

Thanks for the reply Kevin. Any info I can get always helps. From what I can see the only additional buttons are for the cruise functions. I can't remember if I took these switches aparts too. Are they resistance coded as well?

I too was aware of the company that will convert my stock steering wheel to wood, but I also can't shell out $400-500 for this. I picked up my '02 wood wheel from eBay for $50, so I figured it was at least worth a try.

I'm also concerned about the airbag issue. But right now I'm just trying to figure out one thing at a time. I may go ahead & try to splice the new switches into the stock wiring & see if it will work. Do you think there would be any risk of harming the system by doing this?

Thanks again for the info. As I mentioned before, every little bit helps.

Stephen K.
96 STS

96STS -

I can't imaging that hooking up the switches on the 02 wheel will hurt the PCM on the 96, it is just reading the resistance value sent down by the switch press and interpreting that value as a certain switch being pressed. If the values are different, you will either get unpredictble results or nothing at all if the values are too far off the range the computer expects to see. Rember too that there is a 12V line on your existing setup to power the backlighting (micro light-bulbs) in the switch paddles. If this gets cross connected to the switch outputs, it could smoke the PCM or IPC and who knows what else. Be exceedingly cautious in making changes like this.

Having said that, this will almost certainly require cutting up the factory harnesses on both ends, something I think is a bad idea. Then, if it doesn't work and you have to go back to stock, you've got a real mess.

In addition, unless you come up with a way to make good secure connections on the wiring after cutting of the harness connectors you'll end up with all kinds of problems down the road if wiring comes loose inside the wheel. Remember, the steering wheel has to travel it's full rotation without pulling or snagging the wires at any point in the turn radius. If the harness is too tight, or is not properly secured, or the wires are not connected together in some secure way, they will end up pulling apart. Then you have to tear it all apart again to fix it or get rid of it if it turns into to much trouble.

As to the cruise buttons, I don't know if these are resistance-coded as well, or if they have dedicated signal lines back to the computer. If they have dedicated lines then they could be left disconnected and ignored. If they are resistance coded, they may cause unpredictable effects if they are ever pressed. I've not seen a wheel from a 2002 STS dissected so I cannot say how this is setup.

I'm afraid I can't offer to much more detail as I am not personally familiar with the 1996 or 2002 STS, and while I know the operational basis for the steering wheel controls themselves (I have been trying to find a way to add them to my 1995 Deville, but have not taken the jump just yet) the particulars of interchanging wheels of different configurations from different years is beyond the scope of my knowledge without being able to see the car and the parts involved, and looking at the service manuals.

I'd say there is at least a decent chance you can get this to work, but it will likely be pretty involved to make it work seamlessly.

Kevin