2003 bmw 5 series no crank, good battery

[Nate]

Hello,

This drill weekend I towed a 03 BMW 5 series about 100 miles back to the owners home. It's a well kept 5 series, with 130k on it.

Battery has power, but we hooked up jumper cables just because, and no change.

Key turns in ignition, but will NOT crank the vehicle. No mechanical noises like the starter attempts to turn, no sparks, nothing. Same story if we put it into park or neutral, attempting to rule out the nss.

We towed the car home, and the dealership dx fee on a no crank condition is 1hr at $130 per hour MIN.

Any and all suggestions are welcome and appreciated.
Thank you!
~Nate

[Angel]

VW's of that era have a factory alarm box between the key and the starter - I'd expect a BMW to have something similar (the box fails, and never sounds the alarm, but never allows you to energize the starter either...)
on the VW, there are instructions on the webs which pins to jumper out that will remove the alarm from the circuit. A Haynes/Clymer manual would probably have the detail you need for this.

IIRC there are another few trips in the system - one checks that the correct chipped key is being used in the ignition. Another checks that the correct/original instrument cluster is installed in the car before allowing a start. (usually they give you an error message somehow though)

On some starters, you can use a screwdriver to jumper from the large + battery cable (on the starter) to the terminal that fires the solenoid - I'm not sure if you can do that on all starters though.

-John

[Zulfiqar]

first would be to test the starter trigger wire itself, then trace backwards, to take out NSS from equation, its best to jump the wiring (beware the starter will now work in all ranges)

MB also have a security lockdown that cuts the circuit if the system detects something and they DO go bad.