2cheap

I brought my 99 NB back to pseudo-stock and passed emissions. Charging was no issue, but I would see the battery light occasionally on very low idle. I was sorting through the A/C system and did the following operations:

1) Realize that I had left the evaporator plug apart - reconnected it
2) Checked the 2 A/C relays - plugged them back in
3) Plugged the cigarette lighter back in - was out from the last time I had the console off. I had to fish the connector out with my fingers.
4) Did several A/C runs - got the pressure where I wanted

All of these operations, I did with the battery still connected, because I'm lazy.

Somehow, all of this has eliminated the alternator's ability to charge.The battery light now comes on a few seconds after starting,

Battery holds 11.2V and falling. Same at the alternator post.

Changed to a new Advance alternator. Same story.

Swapped over to my Megasquirt that has a handmade alternator regulator - no charging.

Spent a little time polishing up grounds and adding an alligator clip to ground the alternator case - that did nothing.

I removed the engine bay fuse block and looked at the white wire - looked good, but I did not unscrew the main fuse yet and really inspect the white cable.

So - I think this means
1) It's not a blown voltage regulator in the stock ECU
2) It's not the alternator, unless I bought another bad one

I am guessing that there is maybe an open in the 2 signal wires from the alternator to the ECU?
Did there just randomly break? Should I run a continuity check back to the ECU?
Is there a way to bypass this ECU control - I guess not, without an NA alternator transplant?

Did I short a cell in the battery when I plugged in the cigarette lighter?

Did I break something in the signal wires? How?

What should be my next step?

Thanks

Braineack

iTrader: (62)

is it plugged in?

2cheap

For sure. The old alternator produced no charging, before I ever touched it or the ECU.
It was working until it didn't.

When I changed the alternator, I plugged the new one in.
I later unplugged it, checked the wires, and plugged it in once more.

bonez8

Did you have the parts store check the old one or new one to make sure it's not a bad run of alt?

2cheap

*** Update ***

Took the battery back to the parts store. Charged and tested good.
Resting voltage: 12.48 VDC
Idling voltage: 12.05 VDC

I did not yet reconfirm that it is only 12.05 VDC at the alternator terminal, but I am sure that is the case.

I think that leaves:
1) Possible bad new alternator
2) Disconnect in the 2 signal wires to the ETU

Are there any other possibilities?

What are my options for getting out of this mess with an internally regulated alternator?