Join Date: Apr 2007
Location: Oxnard, CA, USA
It all depends on when you want the relay block to turn on/off.
You can use the Red/White wire from the GPS plug that is On with the key and Off ~60 seconds after the key. Or if you want Off with the key, use either the extra power socket on the left side of the bike, or the parking light up near the headlight (for which there is a plug & play harness available). Some guys have used the tail light as a relay trigger (for fuse blocks under the seat), but this is also a pulsed DC signal (to make the rear running lights) which only goes to full 12V brightness when the brakes are applied.
Or, if you want On when the engine starts (as opposed to when the key is turned on) then you can trigger off the Low Beam light, although this does require splicing in to the existing wiring.
'13 Dark Graphite Metallic K16GTLD, 24K miles and counting...
'09 Magnesium Beige Metallic K13GT, 60K miles miles and counting...
'02 Mauve Metallic K12LTC, 106K miles and sold
BMWLT#145, IBA# 366, MOA# 111996, SCMA# 24032
All lower 48 states plus Alaska on the K13GT in two weeks . . .
Some people see the gas tank as half empty. Some see it as half full. All I care is that I know where the next tankful is coming from...