Sourcing Power Supply Information

Hello,

I'm having a hard time figuring out which sensors require 12v power, and which ones only require 5v power. I'm working with an E82 BMW 135I, and I'm using BMW TIS wiring diagrams, to figure out connector pin locations. I am however having a hard time determining the sensor power to supply to my sensors, in my new club level wiring harness.

Some of my sensors were controlled with the old factory DME (Digital Motor Electronics), which takes a few high current inputs of up to 40amps. One of the actuators that was previously plugged into the DME on the old harness, doesn't denote specifically whether it requires 5v or 12v, and I'm assuming that it can vary with PWM. In fact most of the wiring diagrams for sensors and actuators do not specifically denote the power supply requirements, which is leaving me a bit in the dark. I can't really test the power supply, as the car is already completely stripped out, with the old loom stored away.

Does anyone know how I can specifically determine which sensors require 12v or 5v, and if the signal is controlled via PWM, should I assume to use a wire that handle 12v? Is there possibly a way to test the power supply without the wiring harness in the vehicle?

Best Regards,

Michael

I can't help, personally, but there are some very smart chaps that should be able to help, but you don't seem to have mentioned the ECU you're using now?

Have you been able to find the OEM wiring diagram/schematic, as that might help you figure some of it out?

Hey Gord, thanks for the reply. I did end up managing to figure what supply values to configure, based on the color of the wires that I put together based on patterns, backtracking to which unit controls it, and using ISTA / AIR from BMW TIS. I am using the Haltech nexus r3, which has a pretty good document on the pin assignments.

If anyone has a BMW, and would like to know the wire color code pdf I made, just shoot me a message.

Thanks Gord.