My 91 b2200 I’m rebuilding

Xoloanon

So if I use that stock wire or find the keyed 12v source nothing gets plugged back into the alternator?

MazdaMitch

Xoloanon correct.
But you do need to plug in the main plug for the alternator or else the alternator won't work at all

Cusser

Xoloanon

Thank you! Got those figured out. Couple questions about the automatic transmission now.

What’s the thing with the black and red wire?

Tranny was really dirty with oil and grass packed all around it. I found this hole and wasn’t sure what it was. No threads with a smaller hole inside.

MazdaMitch

No really sure about the one with the wire on it. I'm new to the automatics myself. That's what's in my new project truck that I have not started on.

I'm sure there is info on that in the shop manual here on this site.

The one with the vacuum tube is the vacuum modulator I think.

I helped my friend replace his.
He was having to constantly add transmission fluid, and we never saw it leak anywhere BUT it always smoked.

This modulator was messed up and it connects to the intake, so the intake was sucking the transmission fluid right into the cylinders and burning it.

Xoloanon

MazdaMitch

I bought this truck for $300 with a locked up motor. I had another rebuilt motor and I’m replacing about every bolt on part and cleaning it all up really good. I have another truck that is a 5spd so automatic new to me also. I have a chiltons manual and couldn’t find the one with black and red wire or that drain hole looking thing in it.

MazdaMitch

Sounds like mine, it's locked up too!

Cusser

Chiltons? Supplement with https://mazdaminitruckin.com/service-manual/

Xoloanon

Does this look like the part I’m missing? The hole is smooth with no threads but I’m finding a threaded part when I search for an oil pressure switch.

MazdaMitch

It does.

Xoloanon

How do either of these parts work in that smooth hole? Sorry for all the questions I’m not a mechanic lol.

Xoloanon

Xoloanon might have figured it out. I think the old sensor is broke off in there.