Current drain through alternator

  • Thread starter Thread starter sbiddle
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sbiddle

I'm posting this in case someone else has a similar problem. About a yr
ago, my '99 Accent would crank slowly if left for more than 2 days. I had
both the battery and alternator checked and they were ok. Using my
multimeter I found out I had a power off current drain of 250ma through
the ECU circuit. Everything ran fine with the car except the current
drain, so the short term fix was to pull the ECU fuse under the hood when
not using the car.
It started to bug me so I traced the circuits attached to the ECU fuse,
and this includes the alternator sensing wire. I disconnected the alt. plug
and the drain went to almost zero. I replaced the alternate and all is
well.
Even though the alternator checked out OK, it really wasn't. Maybe
someone else has a similar experience.
 
sbiddle said:
I'm posting this in case someone else has a similar problem. About a yr
ago, my '99 Accent would crank slowly if left for more than 2 days. I had
both the battery and alternator checked and they were ok. Using my
multimeter I found out I had a power off current drain of 250ma through
the ECU circuit. Everything ran fine with the car except the current
drain, so the short term fix was to pull the ECU fuse under the hood when
not using the car.
It started to bug me so I traced the circuits attached to the ECU fuse,
and this includes the alternator sensing wire. I disconnected the alt. plug
and the drain went to almost zero. I replaced the alternate and all is
well.
Even though the alternator checked out OK, it really wasn't. Maybe
someone else has a similar experience.
Click to expand...

I'd hack in a relay to 'click' the alternator off when you're not
running. Its an ugly hack, but cheaper than a new computer...

The alternator doesn't dictate when its field is activated, its 100%
controlled by the (apparently slightly disfunctional) computer.
Computer is a couple hundred USD, plus I believe labor (will need to be
'keyed' for the car) is required unless you happen to have a hyundai
proprietary programming tool :)

JS
 
I thought it was the computer at first, and I replaced it with a junkyard
unit, but that didn't fix the problem. I thought of wiring the computer
circuit to a relay, but I'm glad I fixed it by finding out it was the
alternator. I sleep better at night now!
 
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