SCT tune and alternator question

[97MarkJA]

1. is the alternator controled by the PCM for charging voltage?
2. if so, can someone point me to the location in the sct tune file? I've searched.
3. what should the 2 wires on the plug read running into the alternator on a 97?

 

[driller]

1. is the alternator controled by the PCM for charging voltage?
2. if so, can someone point me to the location in the sct tune file? I've searched.
3. what should the 2 wires on the plug read running into the alternator on a 97?

1. None that I know of, but there are PCM parameters modified according to system voltage.
2. See above.
3. They are part of the voltage regulator circuit,,, one is battery voltage and the other is alternator voltage. The IC regulator seeks to balance the output of the alternator. Any imbalance causes a current flow which illuminates the Charge Indicator in the Instrument Cluster.

 

[DLF]

1. is the alternator controled by the PCM for charging voltage?

No.

 

[97MarkJA]

Here's why I ask.
I replaced the battery as the old one was week and wouldn't accept a full charge.
Replaced the alternator because it was only showing 12.9v while running.
With the new alternator in it would read 13.8 while running, once the lights and blower were on the voltage would steadily drop.
I replaced the positive battery terminal as well as ran a 4ga wire straight to the alternator.
Same results. While I had it running and everything on I touched the neg terminal and the clamp was HOT!
Replace the neg terminal clamp and checked all the grounds as well as the resistance between the neg terminal-block-chassis-alt housing. All good.
Went through the service manual and both wires on the plug read as they should. Had the alt checked 4 times and it read 14.2v min and 16.1v max
The plug its self could be bad or the fit could be bad but I don't think so.
Still only reads 13.8 and still steadily drop in voltage.
Any ideas?

 

[driller]

The harness plug for the regulator on the alternator is notorious for going bad on some FLM products causing intermittent issues. I would roll the dice and splice in a new one. That's the only thing I can think of.

 

[NoLimit95]

The harness plug for the regulator on the alternator is notorious for going bad on some FLM products causing intermittent issues. I would roll the dice and splice in a new one. That's the only thing I can think of.

I had to do the same thing. My plug was all cracked somehow but after the new one was put on, well, used one, no more battery light. Done this over a year ago and no problems since.

 

[ford nut]

You have to pull over 14v.
Give max a call-------->
Buy a oem cobra alt.

Spend more money.
Box store alts will give you a headache.

 

[97MarkJA]

Could be the plug or an open diode.
I'll check it out.