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Electrical Problem

Discussion in 'Motorcycle Tech Talk' started by ringo912, Aug 12, 2007.

  1. ringo912

    ringo912 Active Member

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    Ok...I need to hear from the electrical experts out there. Left the driveway today and got about a block away and the bike just quit. :mad: I have an 02 Heritage Classic. Rolled over to the curb and turned off the ignition. When I turn it back on I didin't have any lights and when I hit the start button, the bike wouldn't turn over. The only thing that was working was the speedo and odometer.

    Rolled the thing back home and started checking things out. No blown fuses, they were all good. Took the console off the tank and turned it over to find that the plug on the wiring harness that pluges into the ignition switch was melted on one of the lugs. Took the switch apart and the plastic housing was melted around the same lug. So did my ignition switch just take a shi&,:puke: or do I have a short somewhere that I have to track down? Could it be a bad starter relay? Any heelp would be appreciated.
  2. chucktx

    chucktx Moderator Staff Member

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    make sure the connections at the battery are good and clean,including the ground to frame. a bad connection there will tax the weaker link at the ign. switch and cause it to melt. it doenst happen quickly, it usually takes it toll over time. hopethis helps a bit.........have fun!!!:)
  3. charlieharley0057

    charlieharley0057 New Member

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    Check the master circuit breaker

    Hi May not be related but as you are on an 02 Heritage check out the MCB located behind the plastic screen infront of the rear wheel. This has been a problem before (Corrosion) Probably the cheepest HD part you can buy! replace it, waterproof with a plastic bag and forget. Hope this helps.
    Ride free and safe:)
  4. kenfuzed

    kenfuzed Administrator Staff Member

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    Chuck already touched on this but start with your battery connections. Testing the battery from the terminals can be misleading. Sometimes it can be as simple as the ground bolt threaded into the frame. The cables also commonly corrode internally and increase resistance. This will vary greatly depending on where you live (humidity, salt air, heat, etc). Often this condition will fool you because you still have power flowing to your lights and dash. You should remove each cable and test individually with a good ohm meter. If you don't have a quality meter, save your money and just buy 2 new cables for the hell of it. IMHO this is good insurance, and I replace mine every 4 or 5 years for that very reason since I've been stranded with a corroded cable before.

    Ironically, if you read Abby's blog about her cross country trip you'll see how she had a cable give up the ghost as well.
  5. ringo912

    ringo912 Active Member

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    Ok...I ordered the new ignition switch, old one is toast. Replaced the MCB and starter relay. I figure for $15 why not. If I plug in the old switch, the ignition lug on the switch heats up. Until the new switch comes in I won't be able to see if it is fixed. In the mean time I will check all the cables. I do have a very good ohm meter, any ideal on what kind of reading I should get when testing the battery cables? Thanks for all the responses.
  6. hotroadking

    hotroadking Super Moderator Staff Member

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    Check the cables going to ground and to the starter, I had a start bolt back off and it allowed the cable that runs from the main breaker to the starter to break loose, it would be fine for a while, then it would move, short, and trip the breaker, ended up having to pull the battery and oil tank to get to the trans and that's when I found that broken wire. if you pull the battery you should be able to see the nut on top of the solinoid
  7. ringo912

    ringo912 Active Member

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    So here's the latest...I have replaced the MCB, starter realy, passing lamp togle switch, and ignition switch. I have cleaned all the battery cables. I have checked continuity in all wiring and everyting is good. I still have the same problem, when I turn on the ignition switch the lighting fuse starts to heat up as well as the igniton lug on the switch. If I pull the fuse for the lighting circuit everyting is fine

    The ignition switch has 3 lugs on it, A, B, and I. The A lug is accessories, B is main power in, and I is ignition circuit. The ignition circuit goes from the switch to the fuse block and the following 3 circuits are tied into it: Accessories, Lighting, and Ignition. From there it goes to the starter relay.

    The more lights I turn on the hotter the fuse for lighiting gets. I used my multi-testor with the temperature probe. All fuses are fine except for the fuse for the lighting circuit. Since the lighting circuit is tied in with the ignition circuit, the ignition lug on the ignition switch heats up. So some how something is pulling more amps than it should, but not enough to blow a fuse.

    I have 12.7 votes in all the wiring and 14.7 volts coming in form the voltage regulator. So all that is normal. On a Heritage the positive cable from the battery goes directly to the starter, then from the starter to the MCB. Fron there power is fed to the rest of the circuits. So tomorrow I'm going to by-pass the starter just in case the solenoid is going bad. I am also going to start unplugging different sensors one at a time to see if it makes a difference.

    Any help would be greatly appreciated, I'm supposed to be leaving on a trip a week from this Friday. Won't be going anywhere if I don't get tis figured out
  8. chucktx

    chucktx Moderator Staff Member

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    i would pull all the lights first....then start replacing them to see if you have a bad one. i have seen filliments break and fall over to the ground....causing a weak short. i think the problem is in the lighting circuit, as it is the fuse giving you problems. i dont feel that a sensor is causing the problem. but stranger things have happened!!
  9. ringo912

    ringo912 Active Member

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    Ok...I didn't get in from the garage until 10 pm to night. Drank a pint of Rum with a little pepsi.:drunk: Can't read the HD shop bible anymore, I'm going cross-eyed. So I gues I'll start with the bulbs in the morning.:confused:
  10. kenfuzed

    kenfuzed Administrator Staff Member

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    Are you running any high wattage halogens in your headlight or auxiliary lamps?

    I'm actually going to take back something I said earlier about testing your cables and suggest a better approach. Rather than disconnect every cable and wire for resistance testing, a better method is to run a voltage drop test for each wire and connection. That way you don't have to remove everything and you'll get a more accurate reading.

    Start by getting a reading off the battery for a reference point. Let's just say its an even 12 volts. Now move on to each positive wire and test the voltage at each end. Example, attach the red lead of your volt meter to the positive connection at the starter, and the black neg lead to ground (frame or neg battery post). You should see practically the same reading as the battery. If not, excess resistance in that wire is a problem (or one of them). Test each wire within your ignition and lighting circuit. Be sure to test both ends of each wire, for instance attach the lead to the wire connection at the switch and test, then test the end at the bulb socket. The reading for each end of that wire should be the same.

    The same test can be done for testing ground wires, just switch directions for the connection of the meter. To test the voltage drop for a ground wire, attach the black neg lead from the meter to the end of the wire being tested. Attach the red meter lead to the positive battery post. If the meter reads lower than the battery tested (i.e. 9v instead of 12v) then resistance in that wire or path is at fault. Again test both ends of the wire. Don't test with the engine running as the output will vary.

    A voltmeter makes a calculated comparison between the two leads to give its reading. I mention this only because its different than how a meter reads resistance (ohms). In resistance mode the meter attempts to pass a few milliamps from its internal battery across the item being tested. If you try to connect the meter in resistance mode from a negative to positive you will likely blow the meter unless its fused. Just thought I'd throw out that little warning in case someone tries that.

    I'm sure most reading this already know most of this but it doesn't hurt to repeat it for anyone unfamiliar with electrical testing. To sum up voltage drop testing using a voltmeter:
    • Pretest battery voltage to establish a reference
    • Negative (black) meter lead attached to ground or neg (-) battery post, Positive meter lead (red) attached to positive connection (switch, each end of a pos + wire, etc)
    • Test ground connections with Positive meter lead attached to the pos + battery post, Negative meter lead to end of a ground wire or connection. Test each end separately. Little or no drop in voltage should be indicated.
    Most electrical problems I've seen in motorcycles and cars have been loose connections or poor contacts. Best of luck finding your problem.
  11. ringo912

    ringo912 Active Member

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    I have been running 35 watt halogens in the headlight and passing lamps since the bike was new in 02. The only thing I have changed electrically is I added the module to make the rear turn signals function as running and brake lights. I removed the module and still have the same problem.

    It seems my problem is somewhere in the lighting circuit. Here is why I thnk that. The ignition switch on the consloe has 3 lugs on it. Center lug is power in, right lug is to ignition. left lug is accessories. The wire on the igniton lug goes from the switch to the fuse block. Just be for the fuse block it is pig-tailed and feeds power to 3 fuses and the starter relay. It is feeding power to the lighting circuit, security circuit, ignition circuit and the starter relay.

    When I turn the console switch to ignition position, the igniton wire on the switch starts to heat up as well as the fuse for the lighting circuit. The more lights I turn on, the hotter it gets. If I pull the fuse out for the lights everything is fine, the igniton wire does not heat up. Using my multi-testor, I put the temp probe on the lighting fuse. The fuse is at outside temperature until I turn the igniton switch on. Once on, the fuse and the wire start to heat up. The temp gets to about 100 degrees. When I flip the toggle switch and turn on the passing lamps, the temp goes to about 130 degress in about 30 seconds.

    What is strange is that the wire on the igniton lug at the switch will heat up the brass lug enough to melt the plastic around it, but the fuse doesn't blow. Just another note, I have a carb so I don,t have al the EFI circuits to be concerned with.

    Here is what I have done so far: The positive battery cable goes to the starter and from the starter to the MCB. The other lug on the MCB is ower out to the bike. So just in case there was a short in the starter soleniod, I by-passed the starter and went form the battery directly to the MCB.

    I have unplugged every module and sensor on the bike, removed all the fuses except the lighting fuse and removed the stater relay. This way I fugured the only circuit that would have pwer running through it would be for the lights.

    Flip on the ignition switch wire and fuse heat up. The wire that exits the fuse block to feed the lighting circuit doesn't seem to heat up. None of the switches on the handle bars. turn signals, Hi-Lo beam, horn etc., are heating up.

    Thanks for the input, I going to do the voltage drop test today.
  12. ringo912

    ringo912 Active Member

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    Got'er fixed and I'm back on the road. Ya hit it on the head Kenfuzed, the wire that attached to the igniton lug on the switch was corroded inside the insulation from the connector back about 3/4". Actually found it by accident.

    When I did the voltage drop test, everything checked good. I was really scratching my head then. :confused: So I'm talking to my brother in-law on the phone about it and he says, jiggle the wire in the harness. So I put the power wire and the ignition wire together and instead of jiggling them I twisted them 180 degrees and they started to cool off. :) Twisted them back to the original position and they heated up.:mad:

    So I cut about 3 inches of the igniton wire off, put a new connector on it and, problem solved. :D :D

    Thanks to everyone that chimed in to help.
  13. voodoochild

    voodoochild New Member

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    Glad to hear you got er fixed, now get out there and ride!! :D
  14. dts

    dts New Member

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    could that

    i changed my tranny and since then I'm havin problems with my ignition only firing on 1 cylinder when it gets warmed up! is it possible that i have a short at the fuse or ignition breaker and where is the igntion main curcit breaker?
  15. ringo912

    ringo912 Active Member

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    Not sure about your Fatboy but the MCB on my 02' Heritage is mounted under the seatg on the frame just above the TSSM module between the plastic rear fender extension and the back of the battery box. Not sure but I think this is the only MCB on the bike. Maybe someone else can chime in. I think the ignition circuit just has a 15 amp fuse. You can do the voltage drop test that Ken posted on this page to check for a short. Hope this helps.
  16. chucktx

    chucktx Moderator Staff Member

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    dts.........not sure where yours is located, but your service manual will show exactally where it is.........and the manual is the most important tool you will own.......:D
  17. fxdxsteve

    fxdxsteve Active Member

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    he posted the same problem in three different threads and has figured it out its his ignition
  18. chucktx

    chucktx Moderator Staff Member

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    hmmmmmmmmm:banghead:

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