Discussion and questions related to the course Practical Motorsport Wiring - Club Level
I'm installing a flex fuel sensor that requires a 10k Ohm resistor to be wired between its signal and a +5v reference. The Club Level harness construction class didn't cover splicing resistors into the harness, but I know it's commonly done. Are there any best-practices I should know about? Will any 10k ohm resistor work, or are there "automotive grade" components I should be looking for? Is it best to just use a couple open-barrel splices? How do you go about strain relief and environmental sealing in this scenario?
Since you're pulling up a digital signal, the resistor value/precision isn't critical (so any 1/4 watt axial resistor will work fine). You might want to check as your ECU may have a pull-up on a digital input internally (they often do). The easiest way to splice a resistor into wires that enter a connector is solder two wires to the resistor leads such that both wires to to one side if the resistor. Cover the resistor in adhesive-lined shrink tubing.
Now, when crimping the connector terminals, you crimp both wires (one resistor side, and one harness wire) into the same terminal. You do this for both terminals (5V power and signal). The resistor and it's leads should be short enough that it fits under whatever sealing you put on the back of the connector, or attached further "up the harness".
This same technique is used for termination resistor for the CAN bus.