Wow, Four Months And Still It Dies!
Well this certainly is a persistent issue.
The last time I posted on this issue, I suggested either one (Red/Black, Blue/Orange) of the wires from the ignition switch could be related to the problem. Oops I goofed; when the starter motor turns the engine over then the Blue/Orange wire is functioning, as the Blue/Orange wire provides +12vdc to Fuse D (which in turn eventually energizes the Starter Solenoid Relay coil).
If I recall, the motorcycle ('03 ST1300/A) operates correctly for a while, and then suddenly stops with the following symptoms (ignition switch remains in the ON position):
- Neutral indicator lamp ILLUMINATED.
- Oil pressure indicator lamp ILLUMINATED.
- Fuel injection indicator lamp NOT illuminated.
- ABS indicator lamp NOT illuminated.
- Starter motor turns engine over.
- Engine does NOT start.
- Running lamps are ON, but not at full brightness.
- LH headlamp high-beam is ON, but not at full brightness.
- RH headlamp is OFF.
Additionally, when the ignition switch is placed in the OFF position, these symptoms are observed:
- Oil pressure indicator lamp remains ILLUMINATED.
- Running lamps remain ON.
- LH headlamp remains ON.
Lastly, when the motorcycle has not run run for a period of time (or cooled off some), all the symptoms disappear and the motorcycle again operates correctly.
Some of these symptoms can probably be rationally explained away, the FI and ABS indicators may not re-illuminate until the ECM and the ABS Module have been first shut down (+12vdc removed). The Oil pressure indicator re-illuminates when oil pressure drops below a certain value, with the engine stopped, oil pressure is down to about 0psi.
The headlamps are a bit more difficult to rationally explain, as the RH headlamp receives +12vdc from Fuse E, after first passing through the Starter switch, and the High/Low Beam switch. However the LH headlamp receives +12vdc from Fuse I, after first passing through either the Headlamp High (LH) Relay, or the Headlamp Low (LH) Relay. Both relays are enabled only through the High/Low Beam switch which receives +12vdc from Fuse E (Yep, the same fuse that provides power to the RH headlamp). Not easily or rationally explained.
The symptoms that strike me as being truly odd (yes, the whole issue is odd) are the various lamps on at partial brightness. My experience with automotive tail lamps running at partial brightness, is that usually the circuit path to chassis ground has become compromised (corrosion, incorrectly installed bulb, ?), and the voltage finds a different (higher resistance) path to ground, thus completing the circuit, often with a lowered voltage, thus a dimmer illumination. While I don't imagine your issue is caused by corrosion (at the bulbs) nor incorrect bulb installation, I do think that for some reason the circuit path is changing, possibly due to heat, though more likely due to the movement of chaffed wires within the wire loom. There are quite a number of circuits (conductors) that have +12vdc potential, when the ignition switch is in the OFF position, anyone of which could be providing voltage in an unintended manner by way of chaffed wiring (aka short circuit).
I think if I were facing this issue I would focus my attention on two areas:
- All ground connections. Paying close attention to the Ground Cap Recall, and the common ground connection to the chassis, as well as the ground connection to the battery.
- Wiring loom left-side front. After removing the plastic fairings, carefully cut open the sheathing on the main wire loom located on the left-side with the White 24-Pin Connector, for approximately 6 to 8 inches to allow careful inspection of the individual conductors.
What's left to look at?
- Fuse Boxes, corrosion at the fuse boxes see link.
- Main Fuse B (65 amps), perhaps the fuse has a fatigue or stress crack that mostly remains closed, but under certain conditions (heat being an excellent condition) opens up.
- Battery, perhaps the battery has a unique fault that only becomes evident under certain conditions, a voltage meter temporarily installed might aid in identifying this.
- Bank Angle Sensor Relay, perhaps dirty contacts prevent the relay contacts from opening if/when the coil is de-energized... No, this is just wild speculation.
Common sense and patience will go along way to helping solve this issue, however I think luck is what you really need.