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2001 Ford Windstar Overcharging

Tiny
JOCBOBSKINNER
  • MEMBER
  • 2001 FORD WINDSTAR
  • 3.8L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 146,000 MILES
I had a prolonged over charing problem that I caught just before it caused major problems. It blew MOV resistors in the FEM, REM and the cluster. I repaired all of those and replaced the fuses that had blown as well. I have a new motorcraft alternator on it and a new battery. I have check all the grounds, connectors and common rub spots for wires that would cause drain. Everything is fine and I am still getting too much voltage from the charging system that is controlled by the PCM(smart charge system). The PCM had dry connections. At startup I'm getting nearly 20v to the battery. I am afraid to let it run too long to damage all the repairs I made. I am at my wits end and help! What is causing this? Is it the PCM itself?
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Tuesday, December 10th, 2013 AT 1:31 PM

4 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Measure resistance between pin 59 on pcm and chassis ground if less than 10 ohms repair short in generator load input. If same line is 1 volt or more repair short in line. Measure resistance between pin 59 on pcm and gli line if 5 ohms or more repair circuit. Reconnect harness to pcm and turn key on and measure between voltage regulator connector and chassis ground if 2 volts or less replace pcm if voltage is more than 2 volts pcm is ok. Make sure your ground from battery is good as this can effect this. Same with no corrosion on pins to pcm.
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Tuesday, December 10th, 2013 AT 1:49 PM
Tiny
JOCBOBSKINNER
  • MEMBER
  • 3 POSTS
Thanks for the prompt response! Excuse my ignorance but I only have a Chilton manual for this vehicle. How do I tell which is pin 59 on the PCM and gli line?
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Tuesday, December 10th, 2013 AT 2:22 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Shold be c123 which is already in first diagram I sent you. Pin 59 should be marked on the plastic that goes to pcm. Tiny numbers. Like I said before check your grounds which in your case it on transaxle stud not corroded or broken. Actually you should have a p1245 code as well or your check engine light should be on.
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Tuesday, December 10th, 2013 AT 3:30 PM
Tiny
JOCBOBSKINNER
  • MEMBER
  • 3 POSTS
Everything checked out fine thanks for the help. I began to suspect my multimeter and borrowed one and the voltage is normal. So, all the repairs I mentioned in my first post fixed the initial problem of overcharging and sometime over the last couple months the meter crapped out. Thanks again!
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Tuesday, December 10th, 2013 AT 9:02 PM

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