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Old 05-22-2019, 11:49 PM
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wpoll wpoll is offline
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Originally Posted by oldskewel View Post
On the 3.0i, doesn't that cable (that connects to the source cable at the jump port) go straight to the starter, and then another similarly sized cable continues on to the B+ terminal on the alternator?

So in addition to the obvious jump starting,

when starting the car, 200+ Amps flow through that junction (where the two cables connect, immediately behind the jump port nut) from the battery to the starter

and when the alternator is recharging the battery, the generated current flows from the alternator to the starter, through that junction, and on to the battery.

I would have first tried to file / sand off any corrosion. Completely agree about any surface resistance at that point being in a great spot to convert electrical energy into heat.
Not according to the wiring diagrams. The jumper B+ terminal (X6430) has zero current through it except when jump starting.

The diagrams do have some variation though, including no mention of the X6430 terminal at all on some of the early version, so it's possible in some early cars that the connection arrangement is different.
2005 BMW X5 3.0d (b 02/05)
2001 BMW F650GS Dakar (b 06/01)
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