Ironhead Rewire with Thunderheat. Getting horn, back brake and back light, nothing else

[Roane]

Guys,

I've reached out to Thunderheat but wanted to see what forum thoughts might be on this. I'll start by apologizing for the many questions. I had smaller issues going on a different thread but now they seem more global so wanted to make a new thread. While I'm likely over my head here, I don't want to give up so seeking the forum's learned guidance again so i could possibly get my old bike running before Thanksgiving.

Question 1: When I turn the key, I get the rear light on, the rear brake light works and the horn does beep. But I cannot start the bike (no power at all) and no other lights work. Any thoughts?

I followed directions and I have the positive terminal of the battery attached to the Thunderheat switching station brain at the 13 pin black line (battery +). Also connected directly to the battery is the CycleElectric voltage regulator/generator -- through a 20 amp circuit breaker (input (copper post) of the breaker and output (silver post) to voltage regulator. And I have a black battery cable running from what I think is the correct stud of the solenoid going straight to the + battery terminal and the green wire going from the Thunderhead brain to the other large solenoid terminal. (When I touch with a voltmeter I get the same reading on the terminal green wire is attached to as I get when checking voltage at the battery. I also get the same voltage when I touch the voltage regulator.) I've also attached the number 13 pin black cable (battery +) directly to the battery as outlined in their wiring diagram, not to the ignition switch.

Then I have the number 14 and number 15 pin wires (ignition switch) one red and one red with black stripes going from the Thunderheat box to the ignition (which I thought should complete the circuit). No other wires are attached to the ignition.

I also have the 6 pin wire (white with black stripe) from the Thunderheat box attached directly to the coil as directed, instead of coil to ignition switch (I'm assuming I have it on the correct side of the coil but there are no markings).

In the rear harness controller, I was uncertain of what to do with the neutral switch (yellow) so have not attached it to anything.


Question 2: My Right Side handlebar control has two wires coming off for the start button (yellow and brown) but I've only got one wire coming from the Thunderheat right side handlebar control (black start relay switch to pin 5). I'm not sure which wire from the handlebar control to attach (or both of them) and if the other needs to be a ground. The handlebar assembly I'm using says the yellow wire should connect to a white or black stripe harness wire and the brown should connect to a black or red stripe harness wire.

Question 3: I'm attaching a pathfinder LED light that has three lines coming out of it. When looking at the pins from the socket side, there is a red line on the right, a blue line on the top and a black line on the left. There is also a white and yellow lines connected by what looks to be a fuse. Any idea how that connects to the front harness connector (yellow low beam, white high beam, and what is the third wire I need for the socket (red auxiliary power or this is a ground)? I'm assuming all the arrows going down mean I need s ground for the headlight and all the other lights and horn. If I've only got three lines coming out of the headlamp and one is connected to axillary power, I'm not sure how to ground the light.

[Roane]

I'll include some images here, in case it helps.

[sportsterdoc]

A schematic of what has been done may be helpful to solve this without seeing it in person.
Meanwhile, what powers the ignition switch?
Normal is direct from battery through master fuse or circuit breaker.

[Roane]

I was assuming it was running power through the Thunderheart box. This is the major wiring.

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[The Doctor71]

First off, let me say I am not familiar with this Thunder-Heart box at all.... so take anything I type with a grain of salt.

After reviewing the wiring diagram & with all the problems you've listed..... I'd start my basic troubleshooting 101 with....

• pin 13, 14, 15 - rear harness connector...... are they hooked up as per Thunder-Heart specs ?
  • pin 13, directly from battery +ve
  • pin 14, to ignition switch
  • pin 15, from ignition switch
• pin 4 - Right Handlebar Connector. Is it properly grounded ? Are you sure ?
• pin 3 - Right Handlebar Connector. With ignition key on, is pin 3 hot (aka 12v present ?)
  • I'd suggest conducting this test with the negative lead (on your multimeter) on pin 4 & the positive lead (on your multimeter) on pin 3.
• pin 3 - Right Handlebar Connector. With ignition key off, is pin 3 dead (aka 0.0v present ?)

Get these circuits working correctly up front & I imagine the remaining circuits will be a piece of cake to sort out.

If not, then you're beyond my pay grade...... and I can only suggest Thunder-Heart would be your next stop.

[IXL2Relax]

Like the later HD Body Control Module (BCM) the Thunderheart is intended to handle all the power output... The inputs are simple (like with the BCM) wire connections to ground (in most cases) or handle the incoming (minimal current) signals...

Based on the images provided, the handlebar Start Switch & the Kill Switch share a ground connecton on the TH and each have one input line to connect the other sides of each of those switches...

Originally Posted by Roane

I have a black battery cable running from what I think is the correct stud of the solenoid going straight to the + battery terminal and the green wire going from the Thunderhead brain to the other large solenoid terminal.

The GREEN wire from the TH should be the activating wire for the Solenoid (which is a relay) - Be sure you have it connected to the PRIMARY SIDE of the solenoid and not connected to the SECONDARY (HIGH POWER) SIDE of the solenoid.

Since the solenoid is a RELAY, it has a Primary Coil connected to ground all the time and the control is the GREEN wire which provides power to activate the Solenoid when you start the bike. It also has a Secondary set of contacts (like a relay) which will close connection when the Primary Coil is activated. These Secondary Contacts should be fed directly from the Battery and the other side go directly to the Starter Motor...

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[Roane]

Thanks guys,
I'm going to tackle this tomorrow I hope but I think my confusion over whether to share the white common wire between the starter and kill buttons may be the main culprit and I found a wire reversal on my left handlebar that may have interrupted the turn signals.

Couple of followups questions if you have time.

On my headlamp, I've got a white, a blue and a black wire coming out. Any idea if the black is the ground? No directions came with it?

And should I install a separate cube relay in this setup (Thunderheat doesn't believe so but I've been told to maybe do so as a matter of course because it would be more robust. I don't know if that would create an additional issue however.

I'm including a picture of the solenoid wiring. Green wire is going to the Thunderheart. I need to go back and check but I believe I attached the top post to my battery and the bottom wire goes to starter. If so, this sound correct?

And happy Thanksgiving to you all.

[Roane]

So, I got all lights on and working and starter clicks but won't start. Thank you guys for helping me get this far. The battery I'm using isn't the best but it does this even when I've let it sit on a tender a bit and the tender is still connected.

I'm wondering if I have a short somewhere (maybe horn?) Though because when I last tried to start it, the key got too hot to touch and the bike lights shut down. Assuming the breaker flipped. Any thoughts?

Also, do I need a cube relay on this if it's all running through the Thunderheat box with a breaker there? And should I add a second fuse between the red ignition wire and the Thunderheat box just for safety?

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[IronMick]

Originally Posted by Roane

... it does this even when I've let it sit on a tender a bit and the tender is still connected...

Having the battery tender connected does almost nothing. It is putting out only about 1.5 amps [depending on the model], enough to slowly charge the battery over a period of hours, but not enough to assist in starting the engine

When doing this kind of electrical problem solving it is important to have a voltmeter, or a multimeter with a volts setting...

• You can simply test the voltage between the two battery terminals and know if you have enough [12 to 14 volts].
• You can also do a serious battery test by watching the connected voltmeter while cranking the engine - if it goes below 10 or 11 volts while cranking then the battery needs to be either fully charged, or replaced.

[Roane]

Thank you. I have a new battery but was frankly using this one just to test the lights and see if I had the power going in the right direction. I'm concerned with the key getting hot. Does this sound like a short? Also wondering if I should add more fuses ...

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