I have bought a V3 mainboard, MS3 card, relay board and relay board cable from DIY Autotune.
I have a couple of questions about the relay board wiring which I couldn't figure out from the manual.
I understand that the sensor grounds must go to a different location on the engine block to the ECU ground to reduce the possibility of noise or interference. These grounds come in to pins 14, 17 and 19 and join pin 19 on the DB37. I presume that the relay cable from DIY connects the #19 pin back to the main board. Considering that all the inputs and outputs will run through the relay board (I'm not using MS3x), I assume that ALL grounds run through the main ground pad on the relay board and are not separated. Am I missing something?
Also, I notice that there is a constant 12V supply and a switched 12V supply to the relay board, suggesting I leave the constant supply wired hot and connect the switched supply to the ignition switch RUN position (or a separate starter switch). Have I got this right? I am required to have a master battery cut-off in my car for racing so I could (should!) take the constant feed from here- would this cause problems if I need to hit the master switch?
Some background: I am installing them on a Peugeot and plan to use a stepper motor IAC, LC-1 wideband, VR crank sensor (bosch 60-2 originally fitted to the car) and a locked distributor with direct coil control from the main board. I would like to run a relay for the cooling fans via the FIdle output on the relay board.
