Alternator Charging Issue

[ledzilla]

Ok, so I took a look at the wiring installation for the alternator, and I think I'm on the right track. Now, the wiring for the alternator's connectors is a different color because it was a different brand of alternator and conversion pigtails installed, but the connections look the same. That 1.3V wire is supposed to be switched 12V connected to the "blue" wire in the attached diagram. So, where ever that factory green wire runs, yeah, there has to be some damage to it where it occasionally loses some part of the circuit, either through internal damage to the wire or a bad connection at the other end. So if I either repair that wire or for now just run a separate wire providing switched 12V, in theory that should fix the problem.

I have also seen a few things that say the voltage sensing wire shouldn't be connected to the alternator's B terminal, but instead at the point where everything connects for power (along with a 10A inline fuse). In my current setup I'm not sure that will really make a difference since everything sources from the 350A distribution block I mounted to the wheel well. Those connections all feel pretty secure still.

 

[Tiha]

I don't remember which terminal to connect it to but it should be 12v on that wire. It energizes the alternator.

You don't have to, but I used a key switched source. In case something went wrong inside the alternator it wouldn't run the battery dead.

 

[grumpy old man]

For whatever it is worth I am working on an 89 B2 for my granddaughter. I was waiting in line for gas and noticed the charge indicator had dropped way down. I did not shut it off and started checking things out as soon as I got home. I was showing 14.2 at the battery with the engine running so am sure that it was charging but the gauge was still way down. The engine loom has been completely out of the car because of a code 41 I could not find or fix and was completely unwrapped. Every wire in it was checked with an ohmmeter from end to end and checked fine. I did find a resister in the O2 wiring that no one I have talked to has ever heard of, and yes it is a factory part. Just because I happened to have a new one in a box (one with the permanent pigtail that needed to be wired in) and just for giggles I installed it. The gauge came up about halfway to normal. and I drove it for another month without incident. I do not know what state yours originated in but it seems that Ford was doing wierd things to get those to pass Cal smog, and has wiring that does not show in any wiring diagram.

I am now in the process of curing ALL the issues with the B2 by sitting it on top of a shortened 07 Explorer chassis. I will be using the explorer wiring, dash and all other rlated stuff because I need to make it smog legal in the Peoples Republic of California. Drastic yes, but it is the only way to get a decent powerplant in it.

 

[L\Bronco]

I am seriously considering pulling everything and installing a new harness. But that's for down the road a bit. I'm working on doing that already for my '79 Marquis. Between California emissions parts I can't find anywhere and rodent damage to the wiring I'm not left with many options.

I spent some time checking things over until my hands got too cold (can't even put one hand into gloves right now). There are only two wires connected to the alternator. One is the 2ga charging wire that I installed. The other is tapped into the green wire connected to the original voltage regulator plug. I attached a photo of it. I tested the voltage on that wire and it was something like 1.3V. Looking at my available wiring diagrams, I don't see any modules sourcing power or resistors, so it seems like it should be a full 12V there. I wanted to start up the engine and see if maybe there was a difference with it running, but the cold sapped the battery and that damned charger once again failed to maintain the battery. I'll check it out again after the battery has a better charge. But, I'm guessing that maybe there's damage to that green wire somewhere causing a voltage drop. I'm thinking I should try running a fresh wire with switched power to that spot.

pull on the green wire where that scotch lock connector is. (they are horrible for introducing green death into wire. I think a replacement harness is the answer when you are up to it.
Cheers

 

[ledzilla]

OK, so went back out today, and the tested voltage was something like 0.05-0.10. I wiggled that connector around a bit and the voltage fluctuated wildly. So, I cut out the connector and tested voltage on bare wire, it was about 8V. Reconnected that wire to the alternator using some WeatherPack connectors. Still not charging. I verified that voltage was still coming through the connector. I'm going to poke at a few more wires/connections, but if that doesn't pan out I'm going to grab help from someone with two fully working hands to assist in pulling the alternator to get it tested. Make sure it didn't get damaged with this mess.