Guide: Retro fit cruise control to MK3 Golf TDi

Discussion in 'Diesel' started by Dubnutter, Sep 21, 2011.

  1. Dubnutter Forum Member

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    Just thought I would write a quick guide to fitting cruise control to a MK3 Golf TDi, specifically aimed at making your own interface as apposed to connecting up an OEM cruise control stalk which can cost over 120 from the dealer for the stalk and wiring loom. Cruise came as standard in the states, but over here I have not seen one with it fitted (correct me if im wrong) so it might of been a mega money option perhaps. This is the reason why the internet very rarely shows up an OEM stalk and wire harness.

    I purchased a new Passat b5 cruise stalk from work for 15 thinking i could make it work, but its a different fit, switch layout etc etc and would of been too much hassle to adapt.

    The TDi Golf MK3 came with cruise control built into the ECU as standard, and needs a very simple procedure to enable it using VCDS Lite, or by finding a friendly dealer.

    The pictures I have taken are after I did the intsall so I hope they are enough to give an idea.

    You will need the following:

    * 2x momentary "push to make" switches (DONT make the mistake i did and buy "push to break", doh!:p)

    * 1x on off switch

    * 5x mtrs of 5amp cable

    * Heat shrink

    * Soldering iron & solder

    * 4x double ended crimp connectors

    I bought most of the above from maplins very cheaply.


    1) Behind the fuse box there should be a black 4 wire connector with blue/grey "RESUME", red "SET & SPEED UP", white/black "CRUISE ON" and black wires "12+". It is not connected to anything so you have to feel about a bit to find it, it doesnt pull down very far either so be careful, it should pull down just enough.

    [​IMG]

    2) Cut off the black connector and connect a meter of wire to each colour wire with a double ended crimp connector. It would be wise to mark each wire end with a pen so you know which wire is connected to which colour.

    [​IMG]

    3) Route the 4 different colour wires (now extended by a meter each) to a place where your would like the switches to be located. I chose the 3 blanks next to the rear window switches on the center console.

    [​IMG]

    4) Fix the 2 push switches and the on/off switch in a suitable place.

    5) The black wire is the 12+ and should be live when the ignition is on, this should be connected to one side of the on/off switch.

    6) Connect the black/white wire to the other side of the on/off switch.

    7) Connect the blue/grey wire to one of the push switches, leave the other side of the switch unconnected.

    8) Connect the red wire to the remaining push switch, leave the other side of the connector unconnected.

    9) Using 2 equal lengths of wire, maybe about 10cm is length, connect each of the remaining sides of the push switches to the black/white connector on the on/off switch.

    This is a basic diagram of how it should look.

    [​IMG]


    That's the basic work out of the way, the idea is that when the switch is on, either of the momentary "push to make" switches allow a brief 12+ signal to be sent down the red or blue/grey wire to the ecu to. Red is "SET & SPEED UP" and blue is "RESUME & SLOW DOWN"

    Activating the ECU via VCDS:

    Connect to OBD port and fire up VCDS
    Select "Engine control module"
    Select "login"
    Enter the code "11463"
    Select "Do It!"

    If you are succesful there should now be a "G" in the top right ident' block. ie "XXXGXXX"

    Now if all is well and connected properly you should now have working cruise control!!!

    Apparently this guide also applys to the B4 passat too, but I cant confirm this.

    One final note, The switches are basic cheap ones I have used because I just wanted to get it all up and running to confirm it all works, Eventually you can use some more "OEM" looking switches to make things look alot neater. This guide is so you can get it all up and running with the minimum cost and effort.

    If anyone happens to live near me and needs a bit more clarification im more than happy to help
     
    Last edited: Nov 20, 2011
  2. Dubnutter Forum Member

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    I have just realised this probebly should of been posted in the electrics section, sorry, feel free to move it mods :)
     
    Last edited: Sep 25, 2011
  3. A.N. Other Banned after significant club disruption Dec 5th 2

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    I think it'll do here actually.

    Love it.

    Pics would be great, type of switches, location install etc. I'll try to put this on a Passat B4.
     
  4. Dubnutter Forum Member

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    Yeah no problem, bit dark now so I'l pull the trim off etc and get some good pics and part numbers from Maplins and post tomorrow. Total cost was about 6 I think, assuming you already have basic tools and soldering gear etc. And I purchased a OBD cable off the net, its a cheap 10 one and its slow to communicate compared to the official Ross tech ones, but it does the job, and VCDS light allows you to enable it with no problems.

    I would also like to point out that I did the above with help from lots and lots of internet searching as there didn't seem to be a complete guide.

    Works a treat! :thumbup:
     
  5. m1keh Forum Member

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    Chris if your passat doesn't have the 4 wire plug there let me know and I can tell you where you have to pin into the ecu plug.
     
  6. Dubnutter Forum Member

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    Its only something I think I may have read somewhere about the B4, I could of been mistaken. But for anyone that has a mk3 golf tdi and wants a OEM stalk and wiring loom to make it plug and play, I can supply the part numbers, but at a last check the wiring loom was 75 + vat from a dealer that gives me 15% off list, and the stalk was 77 + vat at the same discount level. Not worth it in my opinion.
     
  7. customiz New Member

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    Is this only applicable to the mk3 diesel, or is possible to do this on the rest of the mk3 range??
     
  8. Dubnutter Forum Member

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    Where MK3's are concerned its only the TDi's that it will work with as they are drive by wire so basically the ecu works everything with only an input signal from the tps on the throttle pedal. The cruise control is coded within the ecu.

    Its possible to fit cruise control to anything to be honest, there are aftermarket kits, they use either electric actuators or vacuum actuators and rely on either the main speed sensor or abs sensors.
     
  9. Dubnutter Forum Member

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    Just to add, resume does not also work as a slow down or coast button. My mistake. Its easy to have a push to break switch inline with the power switch to allow slow down or coasting, but to be honest its not really needed.
     
    Last edited: Nov 21, 2011
  10. A.N. Other Banned after significant club disruption Dec 5th 2

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    How would you modify the install if fully incorporating this feature?
     
  11. Dubnutter Forum Member

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    Pressing the brake pedal briefly cancels the current cruise mode, but allows you to use the resume button to lock onto the previous speed setting. Where as using the on/off switch to cancel, also wipes the previous speed memory. The MK3 golf TDi cruise control OEM stalk does not have momentary slow down with resume at that speed when released. So its a basic cruise control that requires you to find your own speed to lock onto. So my suggestion is to maybe put a push to make switch in parallel with the brake switch so you can disable the current cruise and set at the new speed as it is reached on slow down.

    Does that make sense??
    Its a bit of a basic system on the early tdi, the later ones do have dedicated slow down/coast functions.
     
  12. m1keh Forum Member

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    You can add the extra wire to the ecu on most of these cars to get the coast function. Might not work on the earlier pre 96 cars though. Not worth the effort in my eyes though as its a rarely used feature not seen on any new cars.
     
  13. Dubnutter Forum Member

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    True, set and resume are all that is needed. P.M'd you by the way m1keh.
     
  14. LregG

    LregG Paid Member Paid Member

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    All done an working on my mk3...cheers for the info dubnutter:thumbup:
     
  15. Dubnutter Forum Member

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    Pleasure - enjoy!:)
     
  16. LregG

    LregG Paid Member Paid Member

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    I've been thinking on this....you only really need one 'push to make' switch on the dash

    Bridge + (black) and - (black and white) wires and then wire up just the set switch with - (black and white) and S (red) wires going to it.

    To cancel the cruise control with this set up, easiest thing to do is tap the clutch pedal although the brake pedal will kill the system as well
     
  17. Dubnutter Forum Member

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    Fitting a momentary push to break switch in parallel with the clutch switch will kill the cruise control but keep the last speed memory so you can have a coast function and then hit resume to go back to the original speed, or set to lock onto the new speed.
     
  18. Dubnutter Forum Member

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    After upgradeing to a 16bit metal case ecu from an audi a4 tdi. My cruise control stopped working, and my brake and clutch switches were no longer recognised by vagcom and the ecu.
    After some detective work with the engine loom to the ecu, checking the ecu pin layout differences between audi and vw ecu's, and extremely valued help from m1ke and rubjonny the problem was solved. Basicaly, on the golf ecu the brake switch that does not operate the lights, usualy blue, and the clutch switch,are push to break switches, meaning the ecu see's a constant 12v from each until eituer pedal is pressed, the contacts are broken and the ecu see's the voltage drop and knows the pedals are pressed. The 16bit audi ecu reacts to see'ing 0 volts when the pedals are not pressed. And 12v when they are. So a push to make switch is needed for both. The brake light switch happens to work in this manner, so two of these are needed. However, the audi ecu does not provide a 12v pin and a signal pin, just a signal pin, so a seperate 12v ignition live is needed to be fed through each push to make switch. This issue is unique to the audi 16bit ecu, the vw 16bit ecu would work exactly as the old 8bit vw ecu would, so no changes are needed.
    The cruise on switch also needs its own ignition live feed, feeding to the white and black wire. I have not included this in the guide as this is fairly easy to do.
    Audi 16bit ecus are far more common to find, and cheaper. So i thought this may be of some help to someone.

    Parts needed:

    A meter of wire, doesnt have to be very thick atall.

    4 female std spade connectors

    Something to use to tap a couple of ignition live feeds, solder, scotch locks etc

    2x brake light switches. Same as the one that operates the lights ( the one we are not doing anything to) not sure of the part number but best to pop your own one out and show it to a motorfactor etc.

    Changes to be made:

    Remove the brake switch (usualy blue, not the one for the lights) and the clutch switch. Detach the plugs.

    Cut the plugs off, tape up the earth wires (usualy brown and white, should be the same for each plug)
    These wires can be tucked under the dash out the way as they are not needed.

    Bring two lengths of wire from an ignition live point (best from the fuse box somewhere) so each are long enough to reach each switch location. Attach a std size shielded female spade connector to each.

    Attach another of the same type of spade connector to the remaining two wires cut off from the old plug.

    Fit the new brake light switched to the clutch and brake pedal (they may need a bit of a trim with a knife around the mounting area but they will fit) and adjust the plungers correctly.

    Fit a positive live to each switch (doesnt matter which terminal) and the remaining wires.

    And your done. You should now find that the ecu see's all three pedal switches now.
    I will try and get some pictures.
     
  19. Dubnutter Forum Member

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    You can operate the cruise control with the audi ecu, just by changeing the cruise on switch as described above. But two problems exist;

    The cruise control when on, will over rev if the clutch is dipped, not good. (the brake light switch also cancles the cruise control as a fail safe incase all else fails such as the clutch, cruise on and other brake switchs)

    The ecu uses the clutch switch signal, and second brake switch signal, to reduce fueling momentarily to allow for smooth gear changes, and to save fuel when brakeing for long periods such as going down a long hill. So both these functions wont happen without them. The car will still drive fine, but gear changes will be awkward and bumpy, and fuel economy wont be at its potential best on longer runs.
     
    Last edited: Feb 23, 2012
  20. DN5

    DN5 Paid Member Paid Member

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    Hi. Old but great Thread!
    Any ideas if this would work with the mk2 stalks? Ahu fitted into mk2 golf with mk3 clocks and mk2 cruise stalks?
    Thanks.
     

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