Need help with wiring harness from engine.

[maillemaker]

OK after carefully examining the schematic I think I see what you are talking about with the diode. Evidently the diode prevents alternating current and so you get intermittent DC current.

The diode is not my red crimps, the diode I think is under the shrink tubing here:

 

[StarTech]

Correct it is a half wave rectifier setup with the battery acting as a smoothing capacitor.

 

[maillemaker]

Sounds like if I hook up a multimeter from the red wire to ground I should see DC current if my multimeter is set to DC. If I set my multimeter to AC and it detects a voltage on the red wire then it would mean the diode is bad. Sound right?

The last time I tested this (page 1) I was getting 16.8 VDC off the red wire. But I'm not seeing that at the battery. So, there must be a break somewhere I'm guessing and I'm only running off the battery.

From the schematic, it looks like the charging circuit goes all the way back to A1 on the ignition switch, so should detect ~16 VDC there if I have it at the red wire plug by the engine.

 

[StarTech]

No you would still see an AC as it is a half wave circuit. You just will not see the full AC voltage just the ripple voltage. It just easier to see what the waveform is by using an oscilloscope but very few shops even have one as they mostly used in electronics shops where we looking for noise and other problems on a signal waveform.

 

[maillemaker]

I had done some googling and it said if you have a multimeter set to DC and try to measure AC you will just get zero?

 

[Rivets]

Maybe this manual will be of some help to you. https://www.briggsandstratton.com/c...a/en_us/Files/FAQs/alternator_replacement.pdf

 

[maillemaker]

Very nice manual, thanks!