Could anyone who has a 78 Ironhead please post some pictures of the Electrical components?? Fuse Block, Voltage Regulator, Relays, etc.

I recently bought a running 78, but some one really butchered the electrical system. I'm looking to buy a wiring harness and put it back to "Stock", then at a later time possibly restore the bike to Original.

Thanks

 

Original starter relay, bottom of battery box; 4th terminal is not used! ...



Improved, modern starter relay [incorrectly mounted - later moved up under the seat and flipped so wires point down so water less likely to get in]; note top of regulator under relay ...



Starter solenoid; now have green wire running straight across, between the two lugs, to the terminal ...



Improved [IMO] location for main battery ground cable; much quicker to disconnect when needed; note regulator and relay ...

 

Here is my word description of the wire diagram ...

1[a] GREEN from generator F to voltage regulator
1[b] TAN from generator A to voltage regulator
1[c] TAN from generator A to BLACK at generator lamp

2[a] ORANGE from voltage regulator to connector, then ...
2[b] RED from connector thru MAIN cb to battery +ve
2[c] RED from MAIN cb to starter relay
2[d] RED from MAIN cb to ignition switch B terminal

Note: current passes thru MAIN cb in reverse direction along 2[b] to charge battery

3[a] RED from battery +ve to MAIN circuit breaker [same wire as 2[b]
3[b] BLACK from battery +ve to solenoid long stud
3[c] BLACK from solenoid short stud to starter motor

4[a] WHITE from ignition switch IG terminal [1st key stop] to IGN cb and ACC cb
4[b] GREEN from ignition switch L terminal [2nd key stop] to LIGHTS cb

Note: IG and L are connected by a small GREEN [sg]; at 2nd key stop both IG and L are 12 volts, even with sg removed. So, with sg removed anything connected to IGN, ACC or MAIN will come on at first key stop; anything connected to LIGHTS comes on only at second key stop - a simple, useful modification, especially so that the headlite is not on while using the starter motor.

Two BLUE from LIGHTS cb:
5[a] to rear wire harness connector then GREEN to tail light
5[b] to headlite dimmer switch and thru connector RED to speedo and tach lights

Two wires from headlite dimmer switch:
5[c] yellow to low beam
5[d] white to high beam and high beam indicator

Two ORANGE from ACC cb:
6[a] to rear stoplight switch
6[b] to ORANGE wire connector in headlite bucket

Five ORANGE from ORANGE wire connector:
6[c] to diode, thru connector to BLACK to oil lamp & gen lamp, and to a free spot in connector
6[d] to turn signal flasher
6[e] to front stop light switch
6[f] to the horn switch
6[g] loops back into connector itself to service four free spots in connector

6[h] GREEN from oil lamp to oil pressure switch
6[i] GREEN from flasher to a connector, then two GREEN from connector to left and right turn signal buttons, then VIOLET and BROWN to left and right turn signal lamps

RED from rear stop light switch to rear wire harness connector
RED from front stop light switch to rear wire harness connector
RED from rear wire harness connector to stop lamp

7[a] GRAY from IGN cb thru headlite bucket to RUN switch

Two WHITE from RUN switch:
7[b] to ignition coil [12 volts when key and RUN are both on]
7[c] to START button [12 volts when key and RUN are both on]

7[d] BLACK from START button to starter relay [12 volts while START button is pressed] which results in ...
7[e] GREEN from starter relay RED 2[c] to solenoid small terminal
7[f] Solenoid activates, passing 12 volts along two BLACKs [i]from battery to solenoid 3[b] and [ii] from solenoid to starter motor 3[c]

 

The starter solenoid; green wire is run incorrectly here; should run lower and between the two studs; the loom contains the red and orange wires running to the brake light switch ...

 

[quote=IronMick;8772645]The starter solenoid; green wire is run incorrectly here; should run lower and between the two studs; the loom contains the red and orange wires running to the brake light switch ...

Thanks Mick, that is very helpful. My best guess on my regulator is that it is built into the generator on my bike. But this Puppy really needs some work!!

 

There are some generators, notably from CE but there are others, that have the reg built onto the end of the gen. It is quite obvious if you have one of these. If uncertain post a pic.

 

I started disassembling things today (even though it was 99 degrees). Not sure I can post pic's, last time I tried they didn't post. But I'm game, here goes!

Any suggestions straightening out this mess would be appreciated. See Attached

Thanks

Bottom line is that there are 13 wires total going to these 6 terminals. 1 to #1, 3 to #2, 1 to #3, 2 to #4, 5 to #5, & 1 to # 6.

 

Those are three circuit breakers. There should be four: one 30 amp MAIN, and three 15 amp IGN, ACC and LIGHTS. Here is a pic of mine, more or less original, also 1978 ...



Top right is MAIN, Below is LIGHTS.
Top left is ACC, below is IGN.

Note that IGN and ACC are tied together with a copper strap.

Work thru my word description posted above and note where each wire runs from or to.

To get started ...

MAIN had one red wire going in from the batt+, and three red wires going out. Where does each go to?

ACC has two orange wires going out plus one black. The orange are stock; the black is an extra i added in - it runs to a handlebar mounted voltmeter. Where do the two orange go to?

The connector bottom left with the red and green is running to the tail light - red is brake, green is tail. Look closely and you will see two reds going in and one going out - one in from each brake switch, one out to the brake light.

I intentionally started the word description at the gen, as that is where the electricity originates. It then goes pretty well in logical order. It might be a useful order to follow on your bike.

You can buy a complete replica wire harness for 1978 from J&P Cycles or other sources for a couple or a few hundred $s. Some forum guys have reported that they get the whole thing installed in a few hours.

 

Thanks again Mick.

 

Basic wiring diagram [cyl = solenoid] ...



More wire diagrams and info ...

IronHead Wire Diagrams Etc

Inside the headlite bucket [heh heh] ...



Inside the headlite bucket there is a connector with one orange wire going in and a few going out. The "in" comes from the ACC circuit breaker. All orange wires on the bike are 12 volts with the key on in either the first or second positions.

The other connectors can be confusing, but the wire colors tell exactly what each is. It helps to have a correct, color wire diagram. The Haynes manual has the only color wire diagrams for 1978 and previous. The factory manual only has them in black.