Jan 2020
I decided I wanted to make cruise control work.
At the time I purchased the MK4 Stalk and tried to retrofit the guts of that in to a MK2 stalk, I made a complete mess of it and ended up throwing the stalk out and just getting a normal stalk again. The MK2 indicator stalk just didn't have enough "volume" to it to fit the switch gear/circuit board in it like the MK4 Stalk.
I did some research and found a MK2 CC Stalk on fleabay, however they wanted Moon money for it and for this old girl it wasn't worth throwing 1200NZD at a Novelty.
After hunting fruitlessly for a Wiring diagram for the MK4 Switch (there are plenty of diagrams of where the plug from the switch goes, but none of the inner workings of the switch unfortunately,
I plotted it out and made my own Wiring diagram so I could make my own switch using a combination of junk from Jaycar and a MK2 Switch Blank
The result was passable
The Red Switch is Cruise Control On/Off
the rocker switch is
"I" - Set
"II" - "Resume
and on Paper it worked, under VCDS it was showing all the correct functions and actions, but Cruise control did not work when driving
Now you are probably asking yourself, Why Cruise control in a Dirty Diesel MK2, well main reason was why not, but the secondary reason is I wanted to make use of on the Fly Map-switching as I had 3 Tunes for Various uses on the MK2
1. Stock / Street Rain (Low/No Smoke)
2. Track / Drag (+ Lots of Smoke)
3. Track / Drag with Popcorn. (Also lots of smoke!)
Unfortunately even with a LSD and Pilot Sports this car could become nigh underivable in the Wet, on the freeway in 5th gear with some moisture on the road she would spin up with ease. not so much the case when changing to the placid map
Up until this Time I was having to reflash the ECU with MPPS every time I wanted to change the tune. This was a 20 Minute muck around every time.
Found a fella who could customise your Map to allow for using inbuilt map switching on the ECU, using a combination of Clutch Pedal switch and Cruise control Stalk. This guy wrote it so that the RPM counter would register what map had been selected before reverting back to actual RPM - 1000rpm = Map 1 - 2000rpm = Map 2 etc etc.
How this works is when you depress your clutch pedal if you put the "Set" Button twice it will switch Maps and indicate on the RPM counter. Push it again it will advance to the next map etc after the clutch is released it switches back to normal operation and the RPM continues, this however does not work the same on the MK2 as I am using the original Clocks with no Canbus signal controlling the Tach. So in the end I changed the Base RPM for each Map to help indicate that in cabin
Map 1 - 900rpm
Map 2 - 950rpm
Map 3 - 1000rpm
Video of how it works here - Please ignore the cabin in pieces and hairy legs.
While this worked, Cruise control itself would not, I was going out of my head trying to figure out why it was not working, 2-3 weeks of racking my brain why it wasn't working, It had met all conditions, clutch Switch added, brake light switch upgraded, cruise control switch working.
However, I looked out the window one evening and noticed the faintest glow from the tail lights, The Car had some pretty awful LED Tail lights, Wondering what was up I started going over the electrics with a fine tooth comb wondering what the f was causing this.
In the end it turned out, The MK4 ECU Expects
Incandescent bulbs. and when you first turn the Car on the ECU pulses the brake lights to see if there is resistance on the Load line, because it thought there was no bulb in place it was leaving a slight 3v signal on the line in the case a bulb gets connected or something?.
I bodged in a incandescent bulb with the help of some spade connecters on the back of the MK2 Tail light housing and voila, Cruise worked, and the Low voltage signal had gone and everything was right in the world again.
So yeah, 2-Wins with this pain in the arse saga, I can now Mapswitch from Placid to Savage while on the Road driving.
