Not your average steering wheel control question

[keyser_soze]

I have a 1991 toyota mr2. I plan on putting a 2003 Lexus IS300 steering wheel in it (nicer leather, low pressure airbag, smaller wheel) it is from a automatic that the the up and down shifting buttons on the steering wheel. I want to use these for my stereo controls. I looked and the metra aswc is not compatible. Can I use the PAC unit since its universal? Can I buy the pioneer universal steering wheel controller and just cut the harness and adapt it to the steering wheel buttons?

 

I will be doing this myself, Im not a stranger to wiring but not a genius either. Any help would be greatly appreciated, even if its just letting me know its not possible.

 

[keyser_soze]

I have a x920bt

[1loudls]

well it all depends on the steering wheel itself, and how the buttons are wired up.

 

first if this is a direct replacement, does the clockspring have the exact same connector? and if so are there the right wires coming out of the car side of the connector for the clockspring?

 

the clockspring is the part that allows the wires coming off of the wheel (airbags, horn, and any buttons on the wheel) to be able to rotate with out getting kinked up or breaking a wire.

 

 

if the clockspring in the MR2 doesnt have the extra wires that are needed for the steering wheel (and i dont think it would, unless the MR2 had an option for SW controls) then you will have no way of getting the signals out of the wheel and to the radio. you might have to use the clock spring from the lexus (if that is even possible)without the wires coming out of the clockspring, i dont think that this will be possible

 

now lets say that the MR2's clock spring does have the correct connector, AND the wires on the car side of the harness. this would actually be pretty easy, you will first have to find out which wires are for the buttons, this is best done with the airbag left out of the car. there will probably be two or three wires for this, you will want to make sure that you dont mess with ANY of the wires for the air bag the SW button wires will probably be just like the airbag wires (some cars do have two seperate harnesses at the clockspring, one for the airbag, and one for the other stuff, however there also may just be one harness with all of the wires in there)

 

 

now this is where i start to guess because i dont know for sure how the button really function

 

option 1 (two wire system)

the buttons should either be on the same wires just with different resistances for each button press, this is how almost all factory steering wheel controls work. so there should be a ground wire that feed the buttons, this will need to be grounded at the clockspring, then there is the resistance wire that will show a difference resistance to ground for each button press(both the down buttons that you can see in the picture should be the same resistance, and both the up buttons that you can not see in the picture, should be the same resistance) so you will have two buttons that can control stuff. you then will need to connect the resistance wire from the clockspring to the resistance wire from the PAC module (probably the white wire) and then program

 

 

option 2 (three wire system)

the buttons have there own trigger wire but share a ground wire, the ground wire will of course need to be grounded again at the clockspring, then there should be two wires, one for up and one for down, that will show straight ground when pressing the button (only after the ground input wire has been grounded) for this you will need to basically need to follow the instructions for a harley motor cycle and use two resistors (one for each wire) to be able to give you two different resistances to ground with different button presses. so after you have placed a resistor on each separate trigger wire, then you will need to connect both wires to the resistance wire for the pac module (probably the white wire again)

 

there also could be other ways for the factory buttons to be wired, but these would be the most common way for it to be done.

[keyser_soze]

 

This is what the harness looks like on the steering wheel. The Lexus clockspring will fit in my MR2 (it is the same as the celica gt4 that had the shifting option, alot of celica and mr2 parts are interchangeable) but the harness will not attach to the MR2 body harness. I will be swapping the MR2 cruise control arm onto this wheel (same thing , different connector) and I have the airbag adapter from Toyota (for switching from hi pressure to the low pressure bags)

 

Could I just take the 2 clocksprings (lexus and mr2) and recoil them into one? and use the Lexus connector just for the radio controls?

 

thanks for the reply btw, I haven't got much info on this anywhere. I have a quick steering ratio and I would love to be able to control my stereo without having to take my hands off the wheel.

[keyser_soze]

oh and it is wired the same as your option one. both UPs and DOWNs are the same and linked together. Is there a way to separate the two? I would like to be able to have track up and down on one side and volume up and down on the other side.

 

and keep in mind that these buttons were originally for shifting the auto transmission. So things like the aswc dont list anything for this steering wheel. Im not sure how the PAC works, bare with me Im a mechanic not an electronics guy

[1loudls]

i wouldnt think that you would be able to separate the two ups and the two downs from each other, it would probably be pretty easy to separate them inside the wheel but then you would need at least two more wires going through the clockspring.

 

as far as recoiling them, i have never disassembled one so i really wouldn't be able to say for sure but if they are close enough, it may be a possibility. you also could go with the lexus spring and then just cut off the Toyo harness as solder up the lexus harness to the corresponding wires

 

***COMMON SENSE WARNING***

if this is done wrong in any way you could get seriously hurt. things like the airbag going off while you are working on it or maybe the airbag doesnt deploy later if you get in to a serious wreck. nobody should attempt this unless they know exactly what they are doing

[keyser_soze]

well it turns out my 1991 toyota and the lexus is300 clock spring is the same. well the same connector at least, so i lucked out there. I still have one open space in the harness ( 5 out of 6 wires are used) So now I want to try and at least make it a 3 button system. cant decide if it should be att or mode.

 

and Im well aware of the airbag. it has its own separate connector. I unplug the battery just for extra precaution, and also because airbags are expensive.

[1loudls]

thats cool that it has its own connector, i'm not a big fan of all the wires being in the same harness.

 

 

hell with having one extra wire in the spring, you may be able to get all four buttons to work be able to. you can try to separate both pairs of buttons.

 

now since they are for shifting and not stereo controls, i would think that they are all a straight trigger probably to ground (not differences resistances to ground like OEM stereo controls)

 

you might be able to send the ground signal through the same wire if you add a resistor to just one or both of the wires (different resistances if both) and wire it up kinda like how the directions for the SWI-ps work in a Harley

 

this is all if the switches can be separated (which should be ease since each button is on both sides of the wheel) and have a straight negative trigger.

[keyser_soze]

here is a picture of the connector, with the outputs labeled. the white and the yellow wires that run to both sides connect the shift buttons. if i separate the sides and put a different resistor on 2 of the buttons I should be able to have a 4 different buttons right?

 

I have a x920bt. which PAC module should I get the regular or the updated bluetooth one?

 

http://www.amazon.com/SWI-PS-Steering-interface-Bluetooth/dp/B004P7N236/ref=sr_1_3?ie=UTF8&qid=1311620655&sr=8-3

http://www.amazon.com/PAC-SWI-PS-Universal-Steering-Interface/dp/B001EAWNVY/ref=sr_1_1?ie=UTF8&qid=1311620655&sr=8-1

 

here is the wheel in the car. nice upgrade imo

[1loudls]

yes you should be able to get 4 buttons to control if you separate the two ups and the two downs and add resistors (you will also need to add a resistor to on of wire comming off of the clock spring, since the module can only have one input) you might just be able to have all four buttons have different resistors inside the steering wheel and just use one wire going through the clockspring.

[keyser_soze]

ok so I made a correction to the harness. And to seperate the two sides I would have to cut the white signal wire between the two sides. what about the ground? it shouldn't matter after adding the resistors right?

 

Im going to have a friend look at it who knows alot about electronics (he is a toyota tech) and see if he can get it to work, I just want to have all the info I can for him before hand.

 

also which PAC module should I get the regular or the updated bluetooth one? are they the same just one connects with an aux wire and one is bluetooth?

 

http://www.amazon.co...11620655&sr=8-3

http://www.amazon.co...11620655&sr=8-1

 

[1loudls]

check out this attachment, its a modified section of the swi-ps manual. this is how i would try to do it, leave all the grounds alone, and you can see in your picture where two different wires come into both pins 1 and 2. i would strip back a lot of the tape and cut there to separate the two pairs of switches in to four different buttons, then hook up resistors to each wire and then run them all through the clock spring down the same wire (then you wont have to have more resistors on the other side of the clockspring where the SWI module taps in)

 

i would also make sure to get the newest version of the SWI that you can(ive noticed that some of the older ones have more of a delay than all of the new ones do)

[m5james]

9yr old thread revival on the chance the OP still gets notifications of replies from this forum!!