Vacuum erratic when electric fans turn on

[RustyPile]

Originally Posted by forestb

All that I know is that I used the alternator as a 3 wire when I first bought it in 2009. I then started using it as a one wire around 4 years ago. When I was running it as a 3 wire I had removed the external regulator and put an adapter on on the plug that used to plug into the regulator that rerouted those wires.

I do understand that the voltmeters are not vary accurate. What is a DMV?

I had the battery checked today and it was still in good condition. I took the alternator to get tested but they could not figure out how to hook there Machene up to it. I did notice that when I reinstalled my battery that positive battery cable sparked a little when it touched the post. I have heard that this might mean that I have a ground problem. Also maybe I just need a new alternator sense mine is now 13 years old.

DVM = digital volt meter. What did you use to take those various voltage readings?

If the place that checked your alternator didn't know how, you went to the wrong place. Simply mount the alternator to the machine and hook up ONE WIRE. Spin up the machine and check the output under full load. You need to deal with somebody else..

I think I understand why M.A.D. suggested you stay with a one wire alternator. They aren't complicated to install... I don't like them for several reasons, but what really turns me off to them is the fact that you have to rev the engine so high to get them "excited".

What I'm about to tell you I mean it with absolutely no insult nor disrespect meant. You don't have enough experience or skills to handle electrical work. Reading wiring schematics/diagrams is number one when dealing with electrical problems. Knowing what and how to use the proper tools is also a requirement.

Neither a one wire nor three wire alternator requires an external regulator. So, if you had, or now have an external regulator hooked up, that's one of your problems. Just out of curiosity, what changes did you make to the alternator to switch it between 3 wire and one wire?? Did your battery have to be brought up to full charge before load testing it? If it came off the vehicle fully charged, your charging system is working.

Since I mostly build my own wiring harnesses, I can't truthfully recommend a plug-and-play charging harness.