Charging System Error even After New Alternator

400horses

New Member
Jan 11, 2018
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#1
Hello,

I am experiencing a Charging System fault with my S197. I have searched and searched but I cannot find the answer.

This started a while back with a checkcharging system light that came on after a car wash. I don’t know that the car wash was the culprit, I just remember it was the same night. Anyhow, I kind of ignored it as it didn’t stay on long. Fast forward a week, the car gives a burning smell, and it turns out the mounting bolt on the alternator is so hot that the platic around it melted. Also, part of the bolt literally burned away. So, I cleaned it all, brushed all connections with a wire brush, and applied grease until I could replace the alternator. In the meantime, a new symptom showed up: in the middle of driving the radio would give a POP sound, gauges all reset, and electric steering goes out for a second.

Today, I received my Boss 302 alternator. This was a NEW unit, and bolted right in. Connected everything, turned the car on, and it gave a bad idle, as if it wanted to die. It settled after a few seconds, so I put on the lights, drove for about 5 minutes, and then POP, gauges reset, steering out and back on.

Every post I see says the alternator is going out. However, this just doesn’t seem to be the case, as this was new, out-of-the-box. Also, voltage on battery, after sitting for a few hours since last drive - 12.72v. So clearly this battery is holding a nominal charge.

If there is any insight that anyone can share on where to start checking, I’d greatly appreciate it. This is my wife’s DD (thankfully haven’t sold the backup yet), and it is so stressful.

I have also attached pics of burnt alternator mount.

Thanks in advance to any help you can offer.
 

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David Young

Active Member
Sep 16, 2012
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Clinton, Tennessee
#2
If I were having your problem, I would drive down to my local parts store and let them do a test to my charging system. They will do this for 'free' :)
 

400horses

New Member
Jan 11, 2018
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#3
**UPDATE**

So I unplugged the charging cable from the B+ post of the alternator and replaced it with a 4ga Wire with a 200a fuse straight to the battery.

Worked like a charm for the whole weekend over about 50+ miles. No check charging lights or anything.

Then, 11:30 Sunday night when picking up the wife from the airport, the check charging light comes back on. This time, everything turns off - Lights, Radio, engine, etc. one second later, it’s back on.. then off. Pull over for a second to gather my wits. Turn the car off, breathe, pray, start the car - doesn’t even hesitate. Go about 100 yds and all over again.

By the grace of god it got me home after that without a hitch, but it appears something just isnt staying connected where it should!?

I can take it to a parts store, but my battery is still at 12.68 even on cold mornings. It’s not losing any charge whatsoever, AND it is clearly being charged on those trips in order to keep that voltage where it is.

Are there connections overly prone to failure on s197?