Question: Replacing the alternator

[Evolution1980]

It says that if the Battery lamp is on with the switch off, disconnect the alternator plug. If the lamp goes out the rectifier is bad. This would also show where your drain is coming from.

This would seem to be the case. In that case, based on my (in)ability to locate the proper rectifier, would be to replace the alternator again for $45. (I gotta wonder though why these remans are $45 and brand new ones are in the $140+ range.)

I went back and check power across the regulator's male tabs. It was showing 7.x volts, but the battery voltage itself was still at 12.x volts (engine off)

Your heater blower should not run unless the ignition is on. It should come on with the ignition on as part of the ventilation system. You don't have the option to turn it off completely.

FWIW, my blower has always (or at least for as long as I can recall) run at the slowest speed when I turn the key to ACC ON)
After going through this testing, I'm thinking that I'm seeing some age-related issues.
My blower speed switch definitely has some functional bleed(?) between settings. Notably, between the top two speed positions, the blower will run full speed when it's not supposed to. (This is a bad description since that sounds like proper function.)
I've also noticed that the power antenna goes up...sometimes. It's not like "slower than usual", more like, "it's not even triggering". This antenna function is something new this season.

What is the possibility and/or probability that I had some significant voltage (or amperage) spike that may have caused damage to downstream components? Or, maybe all these things resolve themselves when I replace the alternator... I guess we'll find out soon. I will plan on running down to Summit Racing later today or tomorrow and try another reman'd alternator one more time.
(This is the alternator. AFAIK, it's the correct replacement for the one I'd had for the past 28 years... CLICK!)

 

[Tom Bryant]

I checked across the 2 plug terminals on the 81 both ways, engine off, and got zero volts. I think this is your battery drain and what is showing up on the battery light being on when it shouldn't be. This is probably the result of the alternator having a bad rectifier and possibly a bad regulator. With the engine running do you have 13-14 volts at the bat terminal on the back of the alternator?

I checked NAPA and they have the right rectifier for $40.29 and the regulator for $22. Hard to justify not buying that AC Delco reman.

Sounds like the antenna might have a bad relay or possibly a problem inside the antenna assembly itself. I'll scan the diagnosis charts and email them to you.

Tom

 

[Evolution1980]

I checked across the 2 plug terminals on the 81 both ways, engine off, and got zero volts. I think this is your battery drain and what is showing up on the battery light being on when it shouldn't be. This is probably the result of the alternator having a bad rectifier and possibly a bad regulator. With the engine running do you have 13-14 volts at the bat terminal on the back of the alternator?

I checked NAPA and they have the right rectifier for $40.29 and the regulator for $22. Hard to justify not buying that AC Delco reman.

Sounds like the antenna might have a bad relay or possibly a problem inside the antenna assembly itself. I'll scan the diagnosis charts and email them to you.

Tom

Thanks, Tom. I haven't put the alternator back in [to check voltage at the battery] since I'm gonna be replacing it today or tomorrow. Fingers-crossed that many or all of these problems go away with the replacement.
However, when I did check voltage at the battery prior to removal, it was in the expected 13-14v range.

 

[Tom Bryant]

I hope so. I'm not all that familiar with what kind of odd things happen when internal components go bad. I just emailed the antenna diagnosis flow charts to you.

 

[Evolution1980]

I kept forgetting to update this thread...
Replaced the alternator and all the gremlins noted above have disappeared, except for the antenna. I think I just have a flaky connection because it has occasionally decided to operate as it should.

 

[Tom Bryant]

That's great news. Ended up being a cheap fix too.

Tom

 

[AGVI]

I hope you figure this out!

 

[Evolution1980]

I hope you figure this out!

I did. I replaced the alternator with a remanufactured one. Easy-peasy.
And I took the idea from SS327 to rotate the housing so the wire didn't have to stretch as far.