1978 1150 Thunderbolt Wiring HELP!!

[spitfireap]

I just replaced the corroded wiring harness on my 1978 1150 "Tower of Power". I was careful to take photographs and label the old harness before removing it. Unfortunately, it was so corroded that many wires fell apart as I removed them which is making installation of the new harness more difficult. I need help with the wiring of the red wires on the new harness. According to a wiring diagram I found for this motor, the red 18 gauge cable goes to the 2nd post up on the switchbox and it also connects the rectifier to the switchbox via jumper (ignore the arrows in the pic).

The photo of the rectifier I took before disassembly has a jumper coming from a different post of the rectifier (one with a cable from the stator). (Also, what's the dark red cable attached to the rectifier labeled "G" at the harness in the diagram above? That color is not included in the index at the bottom right of the pic. I have 2 extra cables from the harness that I don't have connected to anything (orange and brown). I know brown is for the tachometer (which was disconnected on my boat) but what's the orange for?

What's the right answer? These 2 seem to disagree. Finally, here's a pic of the setup of the new harness so far. What's the right way to wire the red cables? What do I do with the orange cable (right now I have it taped off since the instructions say to do that if not used).

Any info would be great. Thank you.

 

[Chris1956]

Two things you need to know. The orange wire is for newer motors. It has no function for your motor. Also, the wiring colors changed a few years after your motor was made, although it sounds like you have the old wire colors.

The brown wire needs to connect to one of the yellow wires at the rectifier. It doesn't matter which one.

The red wire on the rectifier can connect directly to the harness, to the battery side of the starter solenoid or to the red terminal on the switchbox. It makes no difference, as long as it has a good connection to the battery voltage.

Hope that helps

 

[spitfireap]

It does, and it would explain the setup I had before. So connecting the red from the harness to the + on the rectifier, then jumping from that + to the red post on the switchbox would be ok? Thanks for the help.

 

[spitfireap]

Also, does it matter which way the yellow wires from the stator connect to the 2 posts at the rectifier?

 

[kck8385]

You can wire the harness red directly to the red terminal on the switch box and jump to the rectifier or do it the other way around it doesn't matter. Also it does not matter which yellow wire goes on each of the rectifier posts. Just don't use the + terminal.

 

[spitfireap]

So the brown is not for tachometer on this harness?

 

[Chris1956]

Yes, the brown wire is for the tach signal. It needs to be connected to the AC side of the rectifier. Either yellow rectifier wire is acceptable.