I recently installed a 2004.25 (after D85978) wood and leather steering wheel in my MY2002 car.


Generally, an easy install, essentially plug and play; the wheel, airbag, horn, and audio controls are all direct changeover.


I could not test the cruise, because the switch that was in it was toast, so I ordered up a NOS replacement from the UK, when parts for the cars are readily available.


I had already rung out the existing switch, to see what was what signal wise to the computer. Turns out that the switches are resistive, and that the function of the ECM responds to the amount of resistance coming down the line; it just sits there at about 4300 ohms when not in use, and the computer decides what to do based on the combination of resistance that it sees. I suspect that there is a control voltage in the ecm that normally idles, and that the settings are based on total voltage drop, rather than current flow...sort of makes sense from a programming standpoint.




Here is the issue: after D85978, it looks like Jag changed the ECM...


The resistances that are being sent are the same, but they are mapped to different functions, and the on/off switching control, which was redundant anyway, has been eliminated in favor of a time based function.


On the new wheel, you simply hold your gas pedal at the desired speed, and push the roller up to set the speed; holding it for about a second enables the controller and set the speed. Same with the down speed, blip it down to lower the speed, hold it down to turn the unit off.


Again, the resistance values sent by the new switch pack are changed, so "Resume" = on, "Cancel" = off, "Wheel Up" = resume, and "Wheel Down" = cancel. There are no controls for "Speed +/Set" and " Speed -/ Reset" present on the wheel.


I wonder if there is a Jag tech or someone familiar with the WDS that knows if this can be remapped by the dealer.


There is no question that the ECM can be changed; the ECM in my car was replaced with a new unit (along with all of the electronic modules, display, and wiring harnesses, due to a lightning strike), and the PO informed me that the dealer had to reprogram it so the original cruise control worked correctly after the refit.



Otherwise, I see a few options: I can open up the control switch, and move the surface mount resistors around so that the controls send the appropriate signals; I will still need to provide an On/Off switch either on the controller or off board somewhere.


I can salvage the roller assembly from another controller and add the [speed +] and [speed -] controls to the existing board, since pads exist for them and the cover is even pre-scored underneath...that will make the controller a right-hand clone to the radio controller and will not look bad at all.



I can slap a blank cover where the speed control is now. or just disconnect it and leave the dead pack there, and figure out a way to mount the old control pack conveniently (that is obviously the easiest way).


Or I can simply use the controls, mismarked, and add external up and down switches, maybe on the back of the wheel (although the second roller would be a much more attractive way to solve that problem).


Really, I can re-mark the controls and make it look factory, but that is for later...


Ideas, comments, opinions, or better yet, the good news that it can be reprogrammed....

 

wa3ra, let me look in the diagrams I have and see if I can spot any resistance differences. There might be a trick that we can do to make things a bit easier for you. Granted, I still think we are going to be possibly messing with some resistances and put in some new resistors.

 

That looks to be the easiest way, Thermo. I haven't been able to find schematics, but I'm comfortable reverse engineering.


The board in the 'new' pack has empty pads in the right places for the missing functions and adding them (ending values of 300 and 600 ohms) will put the missing controls on, only the labels would be wrong.


Thanks!

 

wa3ra, looking at the diagrams for a 2002, 2004.25 and a 2004.5 car, they all use the same resistors for the same switchs. They even use the same pins on the same connectors. So, I am not sure what to think at this point. Could it be that the controls that you have are simply missing the resistors (someone pulled them out or it was never built wtih them so you could put your own in?). The diagrams I have state what resistors go where. So, we can overcome that. Let me know what you are thinking.

 

Let's see if I can explain.


I have a pair of 'old' switch packs one from the wheel, I new old stock. and the same from the updated wheel.


The new switches send the values down the same pins (1 and 3), but the values are not mapped to the same controls. For example, on the 'new' controller, resume sends the 'on', cancel sends the 'off', the scroll wheel 'up' sends resume, and 'down' sends cancel. The new controller does not have the capability of the set +/- .


This is consistent with reports on both this site and the UK site, we can turn it on, but can't set it.


The 2004.25 changes included a 'new' cruise module, where 'on and off' are remapped to the speed + and - being held for at least 1000mS will turn it on and off respectively, so there are no on and off switches. If you have the 'old' style wheel, the switch pack also had the on and off switch removed from the side at that time.


I was under the impression that the cruise was part of the ECM, not a separate physical module; am I wromg, and there is a separate cruise controller?

 

wa3ra, all the drawings I have show the cruise being built into the ECM. No external module just to control the speed.

 

That was what I thought.

Switches open on my bench right now, looks like a 4300 ohm fixed resistor supplies and idle of about 3mA to the ECM full time, the switches are in parallel and switch parallel resistances in as they are toggled.

The 'new' ECM enables cruise when you simply set the speed (move the roller up to the end and hold it), and it really turns it off when you hold the roller down. There ARE a set of unused contacts in the switch pack.

It looks like redoing the board will be easy, big surface-mount resistors, just have to get a pair for the 600 and 300 ohm settings, and I'll cannibalize another roller setup and the switches from another switch pack to create my on and off switch.

It looks like that is what Jag had in mind when they designed the circuit board, and for whatever reason, they changed it.

 

Here is the heart of the old switch. This is a small printed circuit board resistor matrix.

The value of the resistance and the corresponding function are listed.

That is a US dime for size comparison.

 

Wa3ra, I have a extra roller switch. I suck at circuit boards. Would be happy to pay you for your time and make me up one. Let me know.


Thanks,
The Dr!

 

I'll let you know if it works out, it looks promising...

I hope to get it done this weekend, we have to drive down to Hershey on Monday, and that stretch of 81 bites without cruise!

 

Yeah! The Jag has cruise control again!

It took me over an hour last night (in the dark) to get the airbag off, and the steering wheel and clock spring out, then I tore the wheel down and did the requisite surgery on the control switch pack very early this morning.

I was not quite as I planned it. The printed circuit board CANNOT be modified so that the controls match the markings.

The engine computer could have been reprogrammed, but Jaguar blocked that option in their software.

A NEW ECM would need to be fitted and programmed, unless you can find a dealer with the OLD wds software who would be willing to do the flash!


I ended up adding a second roller wheel to the existing control pack. All I need to do now is relabel it so the controls match the switch markings, but otherwise it works well.

I'm going to examine the possibility of rolling a new circuit board that will have the controls in the right locations, although ergonomically, the layout I have now actually makes sense.

 

Ok so what did you wire up to get it to work. Like I said I have one for my sport I would like to do. what wires went where.

the doc needs some assistance

 

Hi, Doctor!


Originally, I thought I could rewire or rework the resistors using the original board. The board is set up by placing the resistors in series, so they 'add up' for the "controller present" signal to the ECM.


As you hit a switch, the resistance associated with that switch is SUBTRACTED from the array; the switch more or less drops a short across the matrix, disconnecting the previous resistors:






That subtractive technology is the issue.


The existing controller has the internal connections and components to add a second roller for the set +/- controls, so I opened up the hole, and inserted a roller from a second switch pack in it. The controls are different from the markings, but all of the controls are present and working as they should. See the earlier picture for what they do at the moment.


To get them to work as marked, we still need to add the roller (or a pair of momentary push buttons), but to use the existing board, I would need to break the circuit traces and hard wire the switch pads to the various "correct" resistors. The other option would be to simply create a new pc board to do the same thing.


With a spare cruise or radio control to get the roller assembly from, the job I did this weekend is easiest.


Actually, the "on" and "off" being the shrouded switches makes sense, as do wheels for the resume/cancel and set +/-. The only oddity is the down roll on the new switch being set or +, and up being reset or -...but that actually works well, too.

 

After putting some 400 miles on over the last few days, I can report that the modified controls work great, and that the "+" (set) control being on the bottom of the wheel rather than the top makes sense from a 'run it with your thumb' point of view.

Again, the cruise is turned on and off by the existing Resume and Cancel buttons, which means that you have to push them intentionally, you won't just bump them and turn the cruise off accidentally; the existing thumbwheel is 'resume' up and 'cancel' down, and the new thumbwheel is 'set' or "+" down, and speed is reduces by pushing up.

It is a very natural motion; push the switch for 'on', then move your finger forward about an eight of an inch to set the speed.

Dr. Dome, you don't actually need to do any rewiring; the surgery comes in disassembling the switch pack, carefully dremelling and filing the opening using the existing bracket as a guide, then dropping in the thumbwheel and frame from another switch, be it another cruise remote or a sacrificial radio switch pack.

I haven't been able to source the thumbwheel switch from somewhere else yet, but Ford has to have used them somewhere!

The internal frame is kind of tight, but you could certainly substitute some kind of sub-mini switches for the wheel if you can't find a spare pack.

 

hello

did you manage to have a diagram or step by step instructions how you did this?
thanks