Anyone here good with wiring diagrams?

[Sump]

I can't tell if I am being a complete moron but this is a wiring diagram for a DB9 steering wheel.

Some DB9s don't come with cruise control. You can purchase a cruise control switch but it needs wiring into the steering wheel and a computer to register the cruise being there.



From my very limited understanding is it just asking to send those 3 wires from the cruise switch to the rotary coupler??

Seems ridiculously easy to retrofit if this is the case.

[LordLoveLength]

Probably - the new switch will come with wiring to the rotary coupler. What the drawing doesn't show is whether the 3 wires on the other side of the rotary coupler have been fitted. Should be easy enough to eyeball though.

[TooMany2cvs]

Sump said:

From my very limited understanding is it just asking to send those 3 wires from the cruise switch to the rotary coupler??

Seems ridiculously easy to retrofit if this is the case.

Looks to be, assuming the wiring from rotary coupler to ECU is there, and that the rotary coupler has the right number of tracks.

But then you need to talk nicely to the ECU, and persuade it that there's cruise installed. And one of the three is illumination anyway.

[Sump]

Well Astons solution is to fit a new wheel with cruse already on it and then flash the car with cruise.

Indy solution is ever so slightly undercutting the dealer by fitting the cruise switch to the existing steering and flashing the car.

My solution is to spend £50 on the switch and £50 on the flash, thus saving £350 odd for what looks like some very easy work.

[Sump]

Well I hit a block. I'm not willing to go along with my wiring assumption and there's no concrete info with whether I am correct or not. Took the steering wheel off and took at look at that coupler. Logic would dictate the 3 wires go on the right below the others but as this wiring diagram is slightly confusing/ pictures you see with the cruise already fitted on wheels. I am bordering giving up and just lobbing a new wheel on.

If anyone is interested, this is where I got up to.

http://imagizer.imageshack.us/a/img540/5922/Lmeb7H...

The thing is with it fitted as standard you can see the wires going into that box at the top!

[thehammer]

Don't forget this will be on a bus system rather than a switch wire for each function so don't be put off by there only being three wires coming out.

[shoehorn]

I have a wiring diagram(Heritage I believe)that shows exactly the same as your diagram,
If it only needs a wheel or switch and a re-flash then the wiring car side of the coupling will be there.
I cant see A-M making equipment specific looms for what is a low volume car,I would imagine that even mainstream manufacturers don`t do it any more.

1 wire c0749-4,as already mentioned is for lighting the switch the other 2 wires,c0749-1 is supply and wire c0749-3 is return,as it shows.

[Sump]

Picture of the back, kinda cleared it up now! Can see what's going on more clearly.

[anonymous-user]

thehammer said:

Don't forget this will be on a bus system rather than a switch wire for each function so don't be put off by there only being three wires coming out.

Looking at that diagram it's not "Bused" (CAN or LIN) it's using a resisitive divider as a selectable pull down voltage feed to the primary Powertrain Control Module (PCM). You can see the resistor ladder values in the diagram.