UPDATE 2 -
I took out the battery to get at the contacts on the alternator. Reasonably convinced that the function of the light blue wire is to provide a ground to the charge indicator lamp, I disconnected that cable from the alternator, energized the system with jumper cables to the hot leads off the battery and the ground strap, and grounded the blue wire. When I turned the key to on, the charge indicator came on. A great relief, at least I don't have to hunt down a wiring harness flaw.
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Since I wrote the below, I've done some more web poking, and it appears that the wire to the charge light isn't necessary for the alternator to work. I think someone else may have pointed to this link, but I had to find it my own way. I'm going to do some continuity testing before I do anything else.
http://www.ibmwr.org/ktech/charge-light-glow.shtml"The light grounds (bl) through the alternator diodes until alternator output equals battery output, thereby providing a positive on both sides of the bulb, which makes it go off."
Nothing blown up. Yet.
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Hi folks,
My charge light doesn't work. I have a sense it didn't work last fall, but I'm not sure. I'm going to go back down to the alternator I just replaced and make sure the connection on the little blue wire is good, but other than that, I'm stymied. Here's the story:
1) Replaced the 32 Amp alternator with a Frankenduck 50 amp
2) Installed an Eastern Beaver headlight relay
3) Installed Twisted Throttle Denali D2 lights (one with the relay/modulator built in). Wired it to run hi/low, depending on the headlight setting.
Soldered everything I could, all the lights work nifty.
I'd emptied the tank last fall in preparation for pulling it. Got it all back together last night, put two fresh gallons in, fired right up, and went for a little ride, and filled the tank. I did notice that there was no charge light before I started. Last weekend, since I'd had the battery out and wasn't sure of it, I charged it fully, took it to the local Harley guy, and it load tested just fine.
I've been concerned about the charging system since I bought the bike in the fall. Longest ride I took was about 50 miles, at pretty good speed, and the Battery Tender, when hooked up, showed less than 80% charge (Steady red, no green at all). So, today I hooked up a volt meter to the accessory port, rev'd to 4K and voltage was flat regardless.
I had a LED kit from the Duck, so I figured I'd install the LEDs and then see. Still no charging light. I think something is amiss in the circuit.
So here's the question:
Can I run a wire from the battery positive directly to the alternator exciter connetor, (where the light blue whimpy wire connects) and then do a voltage test to eliminate the alternator as the culprit, or will I blow something expensive up. I've looked in the wiring diagram and I don't see anything between the charge indicator bulb, but on the backside of the that circuit it looks like something runs to the dreaded bulb monitoring unit.
If anyone knows the pin outs on the back of the instrument cluster, the path of the wire from the alternator to the cluster, or any other helpful pre-surgery information, I'd sure appreciate it.
Thanks
Tom
1990 K75
