Here is the four pin plug, and my temporary test lash-up.
Disclaimer:-
The author can accept no responsibility or liability for any loss
or injury resulting from use of the information contained here.
Be aware that there is no guarantee that the information here will
be correct for your particular ECU. I cannot guarantee that it will
work.
Note that installing cruise control is not a particularly easy job
to do. If you are not competant then ask a garage for a quote (I would
suggest an independant VW specialist or an auto electrician).
Note that if you modify your car you may invalidate any warranty and
ought to inform your insurance company.
Do not expect an official VW dealer to help you (other than by
supplying parts). They may not be allowed to help you to modify you car
away from
its standard specification.
Every VW / Audi TDI has cruise control functionality built into the car's ECU, even if the car is not so equipped. VW TDIs have cruise control as standard in the US, and as a factory fit option in other markets, and you will find information on how to use cruise control for your car in the VW instruction manual that came with your car.
This makes it cheap and not too difficult to retro-fit cruise control to a VW / Audi TDI that does not have it.
Although the cruise control functionality is built into the ECU of the VW TDIs, it is often (though not always) blocked in software. Secondly the cruise control switch will not have been fitted.
These instructions are specifically for the Mk3 Golf TDI and Mk4 Passat TDI, with 90bhp engine code 1Z. If you have a different car or engine then it may be worth trying these instructions out. You may also find reference to cruise control switches and wiring in maintenance manuals such as Haynes at http://www.haynes.com/.
Additional information for other cars can be found here (in
German):-
Audi A3
VW Sharan
Mk4 Golf
Here are instructions for a B5 (1997 onwards) Passat
TDI
Notes from someone that used the Audi A3
instructions for a 2000 Seat Toledo
Translation of the Audi A3/Golf 4 instructions
Here are the instructions that come with a VW retrofit kit for Mk4 Golf/Bora
Here are some instructions for an Audi A6 V6 TDI
Details of other VW and Audi TDIs may well be available in German in back issues of Gute Fahrt magazine at http://www.gute-fahrt.de/.
It may well be possible to add cruise control to other cars that use the VW / Audi TDI engine, such as various Skodas and Seats. Let me know if you have any success with one of these cars.
Note that cruise control can be added to VW TDIs with either manual or automatic transmission.
Steps to installing cruise control to your Mk3 Golf or Mk4 Passat TDI:-
1. Testing whether your ECU has cruise control functionality enabled.
Remove the plastic trim panel that is in front of the relay / fuse
panel.
Hinge forward the relay / fuse panel, refering to Haynes manual for
more info.
Behind the fuse panel you should find an unused four way connector with
four wires leading to it. The colours of the four wires are black,
blue/grey, red, black/white. There are a lot of wires there, it
took me at least five minutes to find it.
Check that +12V is present on the black wire when the ignition is
switched on.
Connect a change-over switch between black and black/white wires; this
is the cruise control "on" switch.
Connect a momentary action push-to-make switch between black/white and
red; this is the cruise control "set" switch.
Connect a momentary action push-to-make switch between black/white and
blue/grey; this is the cruise control "res" switch.
I connected these temporary switches via leads by soldering a short
piece of paper clip into the wires, and then pushing them into the
connector.
Now drive the car and see if the cruise control works. Be aware that
the cruise control does not function below about 40kph.
Here is the four pin plug, and my temporary test lash-up.
2. Unlocking the cruise control functionality in the ECU.
You will probably find that the cruise control does not work, in which case you need to reprogram the ECU to support it.
Find an independant VW or Audi specialist who has a VAG 1551 tool. If you can club together with others it may be worth buying 1551 emulation software from Ross-Tech at http://www.ross-tech.com/. I paid a VW specialist for 1 hour of labour to get this part of the job done. In the UK you can find an independant VW specialist in the small adds section of Volkswagen Audi Car magazine at http://www.autometrix.co.uk/.
Select engine control module by pressing "01Q".
Select read data function by pressing "08Q".
Read group 06 by pressing "06Q" or "006Q" depending on which version of VAG 1551 tool that you have.
The 1551 will display a bunch of numbers. The fourth group of numbers, on the far right of the display will be either "0" or "255". "0" means that cruise control is already enabled. If you see "255" then cruise control is locked, unlock it using the following steps.
Press the right arrow key.
For login procedure press "11Q".
Enter the unlock code "11463Q".
Now repeat the above steps and see if that "255" has changed to a "0".
Now repeat the driving test to see if cruise control works. If it does
not work, then there are some things that you can check:-
That with the ignition switched on, +12V is present on the black/white wire when the cruise control is switched "on".
That with the ignition switched on, +12V is present on the red wire when the cruise control is switched "on" and the "set" button is pressed.
That with the ignition switched on, +12V is present on the blue/grey wire when the cruise control is switched "on" and the "res" button is pressed.
That the switch is present on the clutch pedal, and that the two wires are present connecting it to the ECU; this switch is a "normally closed" switch and goes open circuit when the clutch pedal is pressed and disables the cruise control.
That the second switch is present on the brake pedal, and the two wires are present connecting it to the ECU. The brake pedal has two switches; the first is a "normally open" switch that makes the brake lights come on. The second is a "normally closed" switch that goes open circuit when the brake pedal is pressed and disables the cruise control.
3. Installing the switch.
You can either buy a proper VW switch, which is obviously the nicer and safer option, or use you own switches and mount them somewhere convenient.
The proper VW switch ( for a Golf mk3 or Passat mk4 only ) consists of the following parts:-
Indicator Stalk for 92-96 Golf / Vento or 94-96 Passat
............... 1H0 953 513 D 01 C ( the old part number was 535 953
513 F 01 C ).
Connector housing.......... 1H0 953 634
Connector housing.......... 191 972 714
Contact pair .................. 2 x 000 979 129 ( the old part number
was N 903 352 03 )
Contact pair .................. 2 x 000 979 133 ( the old part number
was N 904 886 04 )
wrinkle cable cover ....... 1H0 971 820 E
4 x cable of 800 mm length
Parts can be ordered from your VW, Audi, Skoda or Seat dealer, or are available for about half the cost from Iberparts at http://www.vigonet.com/quas/weli.htm and no doubt other independant VW parts importers.
The connector housings and contacts are to make a four way cable to connect the switch to the connector at the relay / fuse panel.
The crimp contact pairs 000 979 129 and 000 979 133 consist of a 1/2 metre long wire, with a connector crimped to each end. For each part that you order you get two crimps. You cut each wire in half, so that when you order two of 000 979 129 and cut them in half, you now have four crimp connectors. Here is a picture of what you get:-
When you order these wires from a VW dealer, there are three things
that might happen:-
191 972 714 takes four of the 000 979 129 crimps and plugs into the connector behind the relay panel.
1H0 953 634 takes four of the 000 979 133 crimps and plugs into the
new VW cruise control indicator stalk.
This sleeving was specified by the German author who added cruise
control to a Golf. Ordinary sleeving or heat shrink may be just as
good.
This item is the expensive bit. Note that this part is correct only
for 92-96 Golf/Vento or 94-96 Passat.
Please check with a VW dealer that it is correct for your car.
Similar parts are available for other cars.
Wiring: The connector housings 191 972 714 and 1H0 953 634 are numbered. Connect 1 to 1, 2 to 2, 3 to 3 and 4 to 4 using 800mm wires.
Completed 800mm long cable.
Changing the indicator stalk involves removing the steering wheel and airbag. Refer to Haynes manual for details, and only attempt this if you are sure that you know what you are doing.
Here are some brief instructions of my own.
1. Disconnect the battery by removing the negative cable from the battery post.2. Undo the screws that hold the plastic cover to the bottom of the steering column and remove it.
3. Unscrew the two allen head screws on the back of the steering wheel that hold the airbag to the steering wheel.
4. Carefully lift out the airbag and rest it on the steering wheel / instrument binnacle like this:-
5. Disconnect the airbag connector underneath the steering column. This is the flat wire that goes to the slip ring immediately behind the wheel.6. Remove the nut that hold the steering wheel on.
7. Make a mental note of the two small marks, one on the steering and one on the shaft.
8. Carefully remove the wheel whilst supporting the airbag. Put it down where it won't fall or get kicked. I didn't attempt to disconnect the airbag from the steering wheel, and this didn't cause any problem.
9. Undo the screw three screws that hold down the indicator stalk shown below:-
10. Lift off the old stalk pulling the electrical connectors off at the same time:-
11. Install the new cruise control stalk and make sure that the electric connectors are secure.
12. Re-install the three screws, and hook up the 800mm cable from cruise switch to the connector behind the relay panel:-
13. Clip the connector to the bottom of the ignition switch barrel, and run the cable neatly following the route of existing cables. Run it behind the relay panel and fit the relay panel back to its proper place.
14. Make sure that the indicator stalk is in the centre position ( not left or right turn ) so that the self cancelling mechanism is in the retracted position. Put a smear of vasaline on the horn contact (strip of metal that scrapes on the back of the steering wheel), then carefully re-install the steering wheel.
15. Make sure that the marks mentioned in "7" are aligned, and re-install the steering wheel nut.
16. Put the airbag back in the centre of the wheel and re-install the two allen head screws.
17. Re-connect the airbag connector underneath the column, and put the plastic cover back.
18. Before re-connecting the battery, put the key in the ignition lock, and turn it all the way on, then re-connect the battery. Don't ask me why this has to be done, my Haynes manual said to do it this way after removing the airbag; presumably it stops fault codes from entering the airbag system memory.
4. Adding a "coast" switch - optional
The VW cruise control system on earlier models does not include a "coast" function. If you want to add this then it can be achieved by adding a momentary action, push-to-break switch somewhere on the dashboard. Break the circuit to the clutch pedal switch, and add the the switch in series (NOT in parallel). The idea is that if you either press the clutch pedal or press the switch, then the circuit is broken and the car will coast until your either press the "set" button to select the new (slower) speed, or the "res" button to accelerate back to the old speed. Do not remove the clutch pedal switch from the circuit, the ECU needs to know that you have pressed the clutch pedal.
The ECU disables the cruise control when you press the brake pedal for an obvious reason, so that you can slow down without fighting the engine. The switch on the clutch pedal is there for a different reason; it stops the engine from racing if you press the clutch pedal. Therefore if you are not confident that you fully understand this particular modification, then I would advise you to use the system as VW intended, without a "coast" option.
I am told that mk4 Golfs and Boras now include a coast function as standard.
Feedback
If you encounter success or failure, please post it on the forums at
forums.tdiclub.com with as much
info as possible eg:-
Type of car eg. Mk3 Golf.
Year of manufacture.
Engine code eg. 1Z or AHU.
Any variation or clarification from these instructions.
Your feedback will be used to improve these instructions to help others.
Best of luck, and "up yours" to VW of UK for their lies "can't be done on a car with manual transmission", even though this a standard feature on US TDIs with manual trans, and works perfectly on my car, and general lack of help.
Lastly, thank you to Claus over at http://www.tdiclub.com/
and Robert-Jan de Bree for providing me with this information.