Its the green and black wire getting really hot on my starter
Nice post, Slowered! Shayne, that's a page from the ETM - like a flow chart for the starter wiring & circuits. Does it make a little more sense now, or is it even more confusing?
Here's my take on the wiring diagram. The black/green wire looks like it should only carry power at two times.
1. When the ignition switch is in Run position that black/green wire is grounded through the starter.
2. When the key is turned into the 'Start' position, BMW does a little electrical trickery. The unloader relays get +12volts on both control terminals. That cancels out, so the relays shut off. Those two relays are called 'unloaders' because they disconnect non-essential electrical systems when the car is cranking. That gives the starter more amps.
Those "unloader" relays are the normal Bosch 4-pin 30amp units that almost every car on earth uses. The BMW relays look a bit different, but they work the same way. They basically just have a prettier case and an inline resistor to cut down on arcing in the ignition switch. I'd also suspect they also have a diode internally to prevent current flowing the wrong way. If that's true, and the diode is burned out, that black/green wire would short back to main power, and definitely get warm!
I can check my relays tomorrow to verify my little theory. I'd start checking the unloader relays K5 & K7, and the ignition switch. Do you have a multimeter?
Does the battery ever need to be recharged, or does it hold a charge between starts?
