Battery lamp stays on even when ignition is turned off

[ED P]

I recently acquired a 2002 R1150RT. It had not been run in a couple of years. I drained the fuel tank, changed the oil,  and replaced the battery(it was totally dead). The bike started with no problems. All the warning lights went out, but when I turned it off the battery lamp came on and it stays on even when the ignition switch is off. Any suggestion?

[Miguel!]

I really have no idea but... did you try jiggling the key left and right a bit to see if its perhaps a misalignment of the key barrel? Does it go out when you turn the key to handlebar lock position?

[dirtrider]

26 minutes ago, ED P said:

I recently acquired a 2002 R1150RT. It had not been run in a couple of years. I drained the fuel tank, changed the oil,  and replaced the battery(it was totally dead). The bike started with no problems. All the warning lights went out, but when I turned it off the battery lamp came on and it stays on even when the ignition switch is off. Any suggestion?

 

Afternoon ED P

 

That is a strange one, the battery charging light bulb is powered from both  the ignition switch (with key-on) & powered from the alternator (when alternator is charging) so your malfunction could be from either side.

 

You might remove fuse #1 (in fuse box under seat) to see is the light stays on or goes out. 

 

If the light stays on with fuse #1 removed then your problem is more than likely in the alternator regulator. 

 

If the light goes out when fuse #1 is removed  then it is either staying on from being (still)  powered from the ignition switch, OR, something else that is powered from the fuse #1 circuit  is back-feeding  your charging light. 

 

Remove #1 fuse then post back with what happens then we can go from there.

 

 

 

 

[ED P]

Dirtrider

 

I connected the battery and removed every fuse one at a time and the lamp never went out. Thanks everybody for the quick responses,

[dirtrider]

2 hours ago, ED P said:

Dirtrider

 

I connected the battery and removed every fuse one at a time and the lamp never went out. Thanks everybody for the quick responses,

 

Afternoon ED P

 

Well, this is going to be somewhat difficult to track down over the internet (I won't even be easy leaning over the motorcycle).

 

If the oil pressure light is not lit (with key off) then that tells us that the ignition switch  side of the battery charge light is shutting down at key off (re-check this, is oil light coming on with key-on engine NOT running & going off with key-off?)

 

If the oil light is operating OK with key-on, then with the key-off, then the next move is to see if the blue wire in the under-seat round diagnostic connector will light a 12v test light (you need an actual test light as a voltmeter won't put enough circuit load on the blue wire  to tell a bulb side load from a full 12v input from the alternator)-- With a 12v test light ground clamp hooked to a nice clean shinny chassis ground point you need to verify if the test light is coming on at full brightness or at a dim glow measured at the blue wire in the diagnostic connector? 

 

If the test light glows bright (full 12v input) then that pretty well points to the battery charge light getting back powered from the alternator (usually a failed internal rectifier diode). This then needs to be confirmed  by disconnecting the blue wire from the rear of alternator (a BIG pain in the a$$), then checking the alternator point where the blue wire was removed from.

 

If the test light lights when touching the lug on the alternator where the blue wire "was" connected (with blue wire disconnected)  then that points heavily to an alternator internal diode failure or a  regulator failure.

 

If you don't understand what I wrote above ask questions as you need to fully understand the concept to properly preform the tests.

 

Just so we are on the same page here is it the light shown below with the red arrow? 

 

[dirtrider]

More__ 

 

I see that you recently acquired this motorcycle.

 

You might look around to see if the previous owner spliced anything into that blue wire coming off of the rear of alternator (some have used that blue wire to trigger a power relay that initiates only when alternator starts charging) 

[ED P]

dirtrider

 

I understand your process, but getting to the alternator may have to wait due to other commitments. I will let you know outcome.

Thanks.

[ED P]

Which repair manual has the best wiring diagram? It would save me a lot of tracing wires.

[dirtrider]

20 hours ago, ED P said:

Which repair manual has the best wiring diagram? It would save me a lot of tracing wires.

 

Afternoon ED P

 

The BMW SLP is probably the best but almost  all wiring diagrams have some errors due to running changes & they cover many general models. None of the wiring diagrams show true loom runs but just show wire colors in schematic form.

 

There shouldn't be much wire tracing with your problem as it is pretty straight forward. (one blue wire involved) 

 

Your battery warning light is either (still) getting powered from the ignition switch end (at key-off)  then pulled low at the alternator  (this would also show the oil warning light staying on with key-off  if it the oil warning light is working properly).

 

Or it is getting powered by the alternator end (this would then show full 12v power at the blue wire in the diagnostic connector & the blue wire terminal on the alternator will show 12v with the blue wire disconnected with engine NOT running. 

 

Or there is some (non-defined) added (powered) circuit spliced into the blue wire.--- This could probably be verified by simply unplugging the blue wire from the D+ terminal on rear of alternator. If battery charge light then goes out then problem is more than likely inside the alternator, if light stays lit then possibly something powered spliced into the blue wire.  

 

Added: (OR), seeing as that bike was stored for a long period then maybe check your wire harness runs for signs of mouse damage (mice like to eat on the wire harness of the old BMW's).  Could be a mouse induced  short between the blue wire & a 12v B+ wire.

 

 

 

[ED P]

Thanks

[dirtrider]

28 minutes ago, ED P said:

Thanks

 

Afternoon Ed

 

Check your (PM) messages on this site as I sent you a diagram of your battery warning light circuit. 

[ED P]

Dirtrider

 

Thanks for all the help.