EHC replaced w Thunderheart Gen1

K

kevin05bdmcpr

Member
FYI, former HD mech and mech for AIH in Ft Worth in their early days and retired Engineer.
I replaced EHC w BDMs new Thunderheart module w harness 3 weeks ago. All seams fine until today I connected trickle charger as always. The green light came ON showing all okay. Then I lightly slid my finger tips down fork tubes and I felt like an electrical charge. All non-painted parts I feel it.
Strange! I pulled T charger wiring up above battery seeing 0 chance of a short. Still the feeling. Unplug T chgr and back to normal plug back T chgr there's the grn lite and feeling again.
With battery v= 12.6 dc no problem but slight increase in dcv a + charge in frame. BDM told me when I bought it that oem was Positive Ground and new controller converts to Negative Ground system. Zener diodes are like a check valve for voltage. Is there a bad Z diode allowing small v to neg ground?
I'm at a loss. I'm working on someone's AIH and can't spend much time on mine right now. HELP... LOL.
Just converted AIH to Open Belt Primary and replaced the front forks, bearings/stops. Now going through his electrical needs.
Mine is the red BDM '05 Chopper. I must replace rear pulley squeaking/chirping is driving me nuts. BDM now offers new pulley coated with ceramic w same design but I am apprehensive. Why is it coated? Wrong pitch like the oem?


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pauldeepsea

pauldeepsea

Guru
kevin05bdmcpr said:
FYI, former HD mech and mech for AIH in Ft Worth in their early days and retired Engineer.
I replaced EHC w BDMs new Thunderheart module w harness 3 weeks ago. All seams fine until today I connected trickle charger as always. The green light came ON showing all okay. Then I lightly slid my finger tips down fork tubes and I felt like an electrical charge. All non-painted parts I feel it.
Strange! I pulled T charger wiring up above battery seeing 0 chance of a short. Still the feeling. Unplug T chgr and back to normal plug back T chgr there's the grn lite and feeling again.
With battery v= 12.6 dc no problem but slight increase in dcv a + charge in frame. BDM told me when I bought it that oem was Positive Ground and new controller converts to Negative Ground system. Zener diodes are like a check valve for voltage. Is there a bad Z diode allowing small v to neg ground?
I'm at a loss. I'm working on someone's AIH and can't spend much time on mine right now. HELP... LOL.
Just converted AIH to Open Belt Primary and replaced the front forks, bearings/stops. Now going through his electrical needs.
Mine is the red BDM '05 Chopper. I must replace rear pulley squeaking/chirping is driving me nuts. BDM now offers new pulley coated with ceramic w same design but I am apprehensive. Why is it coated? Wrong pitch like the oem?


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Click to expand...
Not knowing much about your system I will take a stab.
May want to try running a separate ground wire to see if you have a good ground? Do you have any schematics of your system available ?
 
Th3InfamousI

Th3InfamousI

Administrator
Staff member
kevin05bdmcpr said:
FYI, former HD mech and mech for AIH in Ft Worth in their early days and retired Engineer.
I replaced EHC w BDMs new Thunderheart module w harness 3 weeks ago. All seams fine until today I connected trickle charger as always. The green light came ON showing all okay. Then I lightly slid my finger tips down fork tubes and I felt like an electrical charge. All non-painted parts I feel it.
Strange! I pulled T charger wiring up above battery seeing 0 chance of a short. Still the feeling. Unplug T chgr and back to normal plug back T chgr there's the grn lite and feeling again.
With battery v= 12.6 dc no problem but slight increase in dcv a + charge in frame. BDM told me when I bought it that oem was Positive Ground and new controller converts to Negative Ground system. Zener diodes are like a check valve for voltage. Is there a bad Z diode allowing small v to neg ground?
I'm at a loss. I'm working on someone's AIH and can't spend much time on mine right now. HELP... LOL.
Just converted AIH to Open Belt Primary and replaced the front forks, bearings/stops. Now going through his electrical needs.
Mine is the red BDM '05 Chopper. I must replace rear pulley squeaking/chirping is driving me nuts. BDM now offers new pulley coated with ceramic w same design but I am apprehensive. Why is it coated? Wrong pitch like the oem?


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Welcome..

You got lots of questions gonna have to unpack this post a bit!

let's hit the low hanging fruit first. Pulley is Teflon coated not ceramic, Teflon will quite it down they started doing it in late 05/06. Go for it will help! Nothing to do with pitch just coated to keep her quiet.

Regarding you electrical issue the new Thunderheart changes it all to standard Harley talk. You now have 12v going everywhere whereas before ya had 5v at the controls etc.

Sounds to me like you just have a bad ground somewhere something is shorting out. Although you say it's only when on trickle? What about when bike is running and you have 14.4v. Check the headlight bucket to make sure it's got the upgraded ceramic plug not the OEM plastic one.

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K

kevin05bdmcpr

Member
I knew Teflon duh my bad. Headlight plug I think is plastic. Memory failing duh how did we start off? Oh there is a slight short no doubt. When the green light comes on it isn't detecting anything to an extent. I'm sure it isn't sensitive enough for perhaps millivolts dc. I'll open headlight tomorrow. If not there then off w the tank and ring-out each plug to ground etc. Thanks

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Th3InfamousI

Th3InfamousI

Administrator
Staff member
kevin05bdmcpr said:
I knew Teflon duh my bad. Headlight plug I think is plastic. Memory failing duh how did we start off? Oh there is a slight short no doubt. When the green light comes on it isn't detecting anything to an extent. I'm sure it isn't sensitive enough for perhaps millivolts dc. I'll open headlight tomorrow. If not there then off w the tank and ring-out each plug to ground etc. Thanks

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Green light? What green light?

I agree with your assessment..headlight first then tank. It's easy to get those wires to rub under the tank not much room

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K

kevin05bdmcpr

Member
pauldeepsea said:
Not knowing much about your system I will take a stab.
May want to try running a separate ground wire to see if you have a good ground? Do you have any schematics of your system available ?
Click to expand...
Thanks for your response. I wish I had a schematic and wiring diagram with the new module. Only have original oem

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K

kevin05bdmcpr

Member
The new Thunderheart has numerous, around a dozen grounds grouped together with 1 connector for neg. battery post

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K

kevin05bdmcpr

Member
Im going to speak with Rich at R&B Cycles here in Nashville there are former big dog dealer. He's a pretty good guy good mechanic you give me some pointers I'm sure. And yes the green lights on the trickle charger and if it detected a short or something amiss it wouldn't give the green light. About the positive ground and in converting to negative ground there's no misunderstanding that's what Big Dog themselves said. It's a quote.

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TapioK

TapioK

Well-Known Member
kevin05bdmcpr said:
Im going to speak with Rich at R&B Cycles here in Nashville there are former big dog dealer. He's a pretty good guy good mechanic you give me some pointers I'm sure. And yes the green lights on the trickle charger and if it detected a short or something amiss it wouldn't give the green light. About the positive ground and in converting to negative ground there's no misunderstanding that's what Big Dog themselves said. It's a quote.

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Click to expand...
Never seen or heard of Big Dog with positive ground, thats why I figured it's a misunderstanding...
 
Jersey Big Mike

Jersey Big Mike

100K mile club
Ok a couple of things to check.

I would actually check the electrical outlet that the tender is plugged into for correct wiring and no ground problems.

The Big Dog and every other modern bike I've ever seen or worked on is negative ground.

I think the confusion amounts from the fact that the switches on the BDM's operate by grounding themselves and sending that ground signal back to the EHC. Traditional wiring would supply power to switch and when activated the switch would pass the power to the circuit.
Both systems are still negative grounded. What gets switched is/can be changed depending on system.

You might want to test with DVM on AC to see if there is a "leak" in the ac like it sounds like.

Does the bike start?
Do you feel the "electrical power" while running?
Does the voltage go up to 14+ when running?
 
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