Greetings from Shreveport, La.
My girlfriend's 2004 1200C is experiencing intermittent power failures. You can be cruising along and all of a sudden all power disappears, and I mean everything. Lights go out , speedo stops, no horn, turn signals, everything goes dark. Then after 5-10 or so seconds, sometimes longer, power comes back. Battery tests good on load tester, battery cables are tight, fuses aren't blowing, charging system seems ok... I haven't got a clue and I need help. Her ability to ride her scooter is what keeps her from killing me (if momma's not happy, nobody is happy ). You know what I'm saying. Any help or suggestions (other than take it to the dealer) will be greatly appreciated. Thanks!

 

I would check the + battery cable where it goes down into the starter. The one on my 2000 just rotted away and gave the same symptoms......

 

Battery cable to starter seems to be in good shape and tight. Starter spins without problems without dragging or acting power starved.

 

First question is: have you changed/modified anything latley? if so start there, if not then I would actully undo the two battery connections and connections at the starter & frame, clean and reattach with di-electric grease.
Next remove all fuses and realys and do the same with them. (including the big BUS fuse)
If that doesn't do it start checking all electrical connections at the ignition switch and if you have a wiring diagram bypass the handlebar mounted kill switch, it may have soap residu from washing that is interupting power although the kill switch sould just stop power to the engine while leaving the lights on.

 

This is the same problem (or very similar) to what I am dealing with. I have isolated the problem down to 12v shorted to ground in the main harness as it routes down the frame behind the motor and into (I assume) the fuse box.

This started for me quite a whie ago and I had it at the dealer for a total of 5 weeks, the first week all they did was reset the failure codes. The other 4 weeks they just tinkered with it and they told me I have the wrong tach installed??, so I corrected the Service Manager on that one. I finally told them to put the bike back together and I will come and get it.

I was troubleshooting and got down to the last segment of main harness and the problem disappeared...I put everything back together and have been riding ever since. My symptoms are I loose ALL lights and horn, but my speedo, tach and odometer still work.

 

Have you checked the ignition switch? Sometimes if there are too many things on the ring with the key, it will wear out the switch.

 

Cables are tight, clean, and in good shape. No visible breaks in braid surrounding wiring harness. All fuses cleaned and reseated including main 30A fuse, and the same with relay in fuse block. (By the way, what is function of that relay?). Fuses all good with none blowing. The bike just completely loses power, all power to everything... no lights, speedo, nothing. Then power comes back and it runs fine until it happens again. Last time it happened power was off 3-5 seconds.

 

Only thing on key chain is factory security fob.

 

It sounds more and more to me like the ignition switch. I wonder if you talk nice to the dealer if they will take it back if it's not the problem? if so, it would be worth a try.

 

My first check, would have been the batt cables, both cables, both ends.
You say that they are 'good'.
Next, I'd go after the switch. Provided I found nothing grounding in harness.
IF you have any kind of realtionship with the stealer, or the mechanic there, 'borrow' a new switch. If it solves the prob, THEN buy it. I do this quite often with parts, but then, they know me, AND SHOULD KNOW BETTER than to trust me, the 'dummies'.
If you haven't splurged for the HD shop manual, do so, B4 someone on here figures out where you live. Best $$ you'll ever spend on 'her' scoot.
Keep postin', the solution will come along.