Thanks very much for the indicator timeout info. My 6 to 60mph fake speed sounds spot-on for testing around 10mph,
The VSS input seems to have a capacitor to ground. I would not do something like that myself ;-(
18V spikes are no problem to that circuit. The CD4072 is rated at 20V. It is the spikes of up to 350V that can occur when the starter motor is de-energised (causes back-EMF) that will exterminate it, and you will not realise it's dead until you eventually switch off the ignition and the engine continues to run ;-)
As to cases, I like the idea of going for white, then it's obvious if a Mark II has been fitted.
What is wrong with the rear brake? I can look into that once this project is under control ;-)
