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02 Ultra tripping 50 amp main breaker

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Big John 57

Member
I have a problem, 02 Ultra Classic that trips the main breaker I have brought this up before in this forum these are the fixes I have tried so far.
1) Replaced breaker first replaced with 40 amp no help then using a 50 amp did'nt trip as often
2) Replaced the ignition switch (was suggested in this forum) no help
3) Replaced main relay switch
4) Replaced battery
5) Checked grounds on chassis
Recap of problem driving along lose all power clock does'nt lose station presets or time within 1 minute power restores bike will restart with a rough idle like computer resets itself, happed today 12 times in a 20 mile ride. Volt meter reads 12+ volts. Any ideas?
 
Big J,

Electrical problems are a (EDIT)
for sure.
Usually when you get a breaker tripping frequently,, to me means you have a short somewhere feeding into that breaker. If your grounding is checking out ok, then you may have a wire that is cracked, or corroded, or vibrating against metal wearing out the insulation, etc....try tracing the wires leading into the breaker and pay extra attention to areas where wires turn 90 degrees or if they are tied together very tightly.
Good luck.

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I remember your other post some time back unless I've got it confused with a similar one. Did you ever determine (or do a test) what you total system amps are ?

By design when a Main (Maxi etc) fuse or breaker goes, it's usually only one of two things. Either the main fuse/breaker is bad OR you have too much system amps going. I don't think you have a short or an individual fuse would have blown first. The main fuse is either bad OR it's doing it's job and preventing your harness from overheating.

When you say the volts are 12+ is that with the engine running ? It should be closer to 14v if the charging system is doing it's job.
 
Big John 57 said:
Volt meter reads 12+ volts. Any ideas?
Click to expand...

While the bike is running? It should read about 13.75 VDC while running at 1K RPM or more.

R_W_B said:
it's doing it's job and preventing your harness from overheating.

When you say the volts are 12+ is that with the engine running ? It should be closer to 14v if the charging system is doing it's job.
Click to expand...
You beat me to it:rofl
 
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Likely you have a "shunt" (parallel) current leakage path (i.e. a wire is shorting to chassis ground)...there are several "normal" idle current "draws" if you will, but these are low current (we are talking about milli-amps or thousandths of an amp) to blow your 50A fuse there is something huge. We are talking about burn mark/arcing and heating, wiring nearby will be discolored or warm to the touch or carbonized black. Remove the headlight/lighting fuse, and "non-essential" items fuses. Disable alarm system as well. Now fire up the bike (figuratively speaking) and see if the fuse blows...you can also purchase an "AMP Clamp Test Meter" to measure the actual current draw coming from the battery. The draw should be only a few AMPS...but with the vibration of the bike and heat it will show up the short if it still is there by heating of the wiring harness. If main 50A breaker does not blow, put in each fuse/branch ckt and wait a bit, monitoring the current...if it jumps up 10 or 15 Amps or more you have found your parallel path and have to troubleshoot from there...good luck and hope you have a schematic/service manual to help you.:s
 
NEWHD74FAN I'm thinking if he's got a short to ground it's gotta be on a "non fused" circuit or it would be blowing a fuse. But I like you idea of testing for it.

He's gonna have to shell out over a hundred bucks minimum to get a decent DC reading amp probe. I wish I had one. Some battery shops have them on their battery testers but he'd have to get the bike there.
 
I am going to borrow a clamp on amp probe from a friend to do a check. I also found a service bulletin from Harley Davidson Safety Recall 0113 Main Circuit Breaker Replacement, reading through it sounds like their great fix is to replace the 40 amp breaker with a 50 amp breaker something I have already done. I have read other blogs that say 01 - 03 Ultra's, Road King's have had these problems Harley started using a maxi fuse and located it away from the engine. I'll let you know what I find out during this week.
 
Big John 57 said:
I am going to borrow a clamp on amp probe from a friend to do a check. I also found a service bulletin from Harley Davidson Safety Recall 0113 Main Circuit Breaker Replacement, reading through it sounds like their great fix is to replace the 40 amp breaker with a 50 amp breaker something I have already done. I have read other blogs that say 01 - 03 Ultra's, Road King's have had these problems Harley started using a maxi fuse and located it away from the engine. I'll let you know what I find out during this week.
Click to expand...

Good luck and let us know what u find, this problem goes back further, my 97 FLHT got recalled for the same problem, they upgraded the breaker and the ignition switch
 
Big John 57 said:
I am going to borrow a clamp on amp probe from a friend to do a check.
Click to expand...

That is a must if you want to get anywhere with this problem.
This is a copy and paste from an earlier thread of yours. Has the problem changed from this earlier description?

"what seams to happen now is when I turn on the running lights along with the headlight the 50 amp breaker will trip after riding for about 5 mins. it will reset with in 1 min and I restart the bike again running ruff. What could be pulling so much current. I use to ride with my driving lights and headlight on all the time with a 40 amp breaker with no problems.I have not added no new electrical items to the bike or had any work done to the bike this just started happening one day"

You really need to measure the current that is being pulled without the lights on. The above could lead you to think there was something wrong with the light circuit circuit when the problem is not the light circuit. Because if the current level was already 40 amps with the lights off (the real problem),, adding just 10 more amps (normal for lights) would cause the breaker to open. (an expected event)

Would you happen to have an ordinary amp meter that has a range to 15 amps DC?
This is an 2002 Ultra Classic,, carb or EFI?
 
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