alternator wiring question

[graybird78]

hi to ALL!

have a question about the wiring from the alternator to the back of the fuse box where there's a junction, to the regulator rectifier:
saturday night coming home from work, all of a sudden the tach stopped working. first thing i checked was the alternator charging... answer NO. checked all fuses, they were good. proceeded to tear seat and gas tank off to get to voltage regulator. thought voltage regulator was bad, replaced with another known good one. same result - no tach. tracing wiring down found a connector behind the fuse box, with 3 white wires and 1 yellow. 3 white wires were melted in half. repaired 3 white wires. everything seems to be working fine now. question is - where does the yellow wire coming from the alternator to the connector, behind the fuse box, go to?... my cycle manual shows the yellow wire but there's nowhere on my bike to hook it. does this wire serve a function?... this is the second time it has melted these very same wires in the same spot. is there something that causes this problem that i need to be aware of? my thinking is that the wiring from the alternator to this connector is too small and can't handle the current and the heat, that it generates.

[TopCatGr58]

Hey there Greybird,

I just looked at a 79SF, and also checked the wiring diagram for the 80SG, and the yellow wire(more burnt orange) is the MAIN power line for the other fused wires/circuits, in other words, it supplies the main power for the other circuits to run off of from the fuse panel! Again, this is according to the diagram!? SO, with yours not connected, not sure why it's running, cause that wire is also linked to the Volt/Reg/Rect, and that's how it monitors the voltage output of the ALT, so with it disconnected, the VR can't tell how much is being put out, and perhaps that's why the wires overloaded and got fried, the VR was telling the ALT to crank out at full capacity since it wasn't getting a signal telling it that it was making power!?!?
HTH? T.C.

[rwtrail]

yellow wire

greybird, hey I just did the same thing as you a couple of days ago. I cant find where the yellow wire goes either. Everything on my bike works and the alt. is charging. Its been a few days since your post, have you found out the answer yet? rwtrail

[graybird78]

hello. answer to your ?. no. I haven't found were that yellow wire goes. my charging system is working just fine. have checked it # of times . it should go somewhere. i'm not done looking just yet. weather here is great for riding so haven't torn it apart to have a better look.

[rwtrail]

yellow wire

hey man, i forgot to tell you that after wiring y alt. up my kill switch is not working. i have ridden more this week than i have all year, i like riding in the fall best of all

[skids]

Re: yellow wire

Yellow wire runs the head-light relay, I do believe.

Originally posted by rwtrail
hey man, i forgot to tell you that after wiring y alt. up my kill switch is not working. i have ridden more this week than i have all year, i like riding in the fall best of all

[rwtrail]

headlight relay

Thanks I'll look some more.