No start problem - a little help please.

[Steve5and6]

No current going to starter solenoid. If I hot wire it (+ to the solenoid), the starter engages and spins normally, so my conclusion is no fire to the solenoid. I also took off the engine control loom from the fuse box and hotwired the wire to the solenoid and the starter spun normally as well, so the wire loom to the starter is OK.

Bentley is pretty silent on diagnosing and identifying components of the starter circuit other than that it says that auto e28's have a starter relay in the left of the driver's footwell. Actually, there seem to be about five relays in there. Prompts a couple of questions

1. Anyone know which the starter relay is?

2. Is there anything else in the starter circuit, other than the key switch, the park/neutral lockout and the relay?

3. Are there any diagnostic tests, other than hot wiring to the solenoid?

4. Anyone have a similar problem they solved?

Thanks in advance for the help.

Steve5and6.

[Jon in Richmond]

I had a similiar problem in that if I jumpered the positive to the starter, it would spin. Turned out to be corrosion of the positive battery cable/terminal.

[Steve5and6]

All terminals new/clean. I can get the starter to engage by sending current to the potitive terminal of the solenoid (at the fuse box wore loom), so the starter, solenoid cables and wiring from the fuse box to the solenoid are all fine. I'm just not sending current to the solenoid.

[RonW]

Try cranking it from the diagnostic connector.

Connect pin 11 of the diagnostic connector to 12V, which is available on pin 14.

The ETM shows the starter relay as being at the bottom of the mess up against the firewall. There are two relays there, and the starter relay is the one on the right.

I don't know that I'd trust the ETM on that point, though. The starter relay has 3 black wires going to it, and one brown & black wire. One of the black wires just loops to another terminal on the relay.